Communication management system, communication method, and recording medium storing communication control program

ABSTRACT

A communication management system, a communication method, and a non-transitory recording medium storing a communication control program, each of which is capable of determining whether to start a communication session with a third communication terminal that requests to participate in a communication session being carried by at least a first communication terminal and a second communication terminal, based on session identification information and location information that are received from the third communication terminal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is based on and claims priority pursuant to 35U.S.C. §119 to Japanese Patent Application Nos. 2013-034146, filed onFeb. 25, 2013, and 2014-023399, filed on Feb. 10, 2014, in the JapanPatent Office, the entire disclosure of which is hereby incorporated byreference herein.

BACKGROUND

1. Technical Field

The present invention generally relates to managing a communicationterminal that transmits or receives image data.

2. Description of the Related Art

With the need for reducing costs or times associated with businesstrips, communication systems provided with teleconference orvideoconference (“conference”) capabilities are widely used. Thecommunication systems allow transmission of contents data such as imagedata and/or sound data among a plurality of communication terminals thatare remotely located from one another to facilitate communication amongthe plurality of communication terminals through a communicationsnetwork such as the Internet.

While communicating among the plurality of communication terminals, acommunication terminal other than the communication terminals that areparticipating in communication may request to participate incommunication.

SUMMARY

Example embodiments of the present invention include a communicationmanagement system, a communication method, and a non-transitoryrecording medium storing a communication control program, each of whichis capable of determining whether to start a communication session witha third communication terminal that requests to participate in acommunication session being carried by at least a first communicationterminal and a second communication terminal, based on sessionidentification information and location information that are receivedfrom the third communication terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages and features thereof can be readily obtained and understoodfrom the following detailed description with reference to theaccompanying drawings, wherein:

FIG. 1 is a schematic block diagram illustrating a communication systemaccording to an example embodiment of the present invention;

FIG. 2 is an illustration for explaining communication between or amonga plurality of communication terminals using the same communicationsprotocol;

FIGS. 3A to 3C are illustrations for explaining image quality of imagedata transmitted or received by the communication system of FIG. 1,according to the SVC standards;

FIG. 4 is an illustration for explaining communication between or amonga plurality of communication terminals using different communicationsprotocols;

FIG. 5 is an illustration for explaining image quality of image datatransmitted or received by the communication system of FIG. 1, accordingto the AVC standards;

FIG. 6 is a perspective view illustrating the outer appearance of acommunication terminal of the communication system of FIG. 1;

FIG. 7 is a schematic block diagram illustrating a hardware structure ofthe communication terminal of FIG. 6;

FIG. 8 is a schematic block diagram illustrating a hardware structure ofany one of the communication management system, relay device, conversionsystem, program providing system, and maintenance system of thecommunication system of FIG. 1;

FIG. 9 is a schematic block diagram illustrating a functional structureof the communication terminal, relay device, communication managementsystem, and conversion system of the communication system of FIG. 1;

FIG. 10 is an example data structure of an image quality managementtable, managed by the management system of FIG. 9;

FIG. 11 is an example data structure of a relay device management table,managed by the management system of FIG. 9;

FIG. 12 is an example data structure of a terminal management table,managed by the management system of FIG. 9;

FIG. 13 is an example data structure of a terminal state managementtable, managed by the management system of FIG. 9;

FIG. 14 is an example data structure of a candidate list managementtable, managed by the management system of FIG. 9;

FIG. 15 is an example data structure of a session management table,managed by the management system of FIG. 9;

FIG. 16 is an example data structure of a conversion management table,managed by the management system of FIG. 9;

FIG. 17 is an example data structure of a data quality management table,managed by the management system of FIG. 9;

FIG. 18 is a data sequence diagram illustrating operation ofestablishing communication among two or more terminals of thecommunication system of FIG. 1, according to an example embodiment ofthe present invention;

FIG. 19 is a data sequence diagram illustrating operation of processinga request for starting communication between or among the communicationterminals of the communication system of FIG. 1;

FIG. 20 is a flowchart illustrating operation of determining acommunications protocol to be used by the communication terminal of thecommunication system of FIG. 1;

FIG. 21 is a data sequence diagram illustrating operation ofestablishing a communication session, before starting communicationbetween the communication terminals of the communication system of FIG.1 when the communications protocol is the same for the communicationterminals;

FIG. 22 is a data sequence diagram illustrating operation oftransmitting or receiving data between the communication terminals ofthe communication system of FIG. 1, when the communications protocol isthe same for the communication terminals;

FIG. 23 is a data sequence diagram illustrating operation ofestablishing a communication session, before starting communicationbetween the communication terminals of the communication system of FIG.1 when the communications protocol is different between thecommunication terminals;

FIG. 24 is a data sequence diagram illustrating operation oftransmitting or receiving data between the communication terminals ofthe communication system of FIG. 1, when the communications protocol isdifferent between the communication terminals;

FIGS. 25A to 25C are an illustration for explaining image quality ofimage data being converted by a conversion system of the communicationsystem of FIG. 1;

FIG. 26 is a data sequence diagram illustrating operation of processinga request for participating in a session being carried out by thededicated terminals, generated by the non-dedicated terminal, accordingto an example embodiment of the present invention; and

FIG. 27 is a flowchart illustrating operation of determining whether toallow starting of the communication session, performed by the managementsystem, according to an example embodiment of the present invention.

The accompanying drawings are intended to depict example embodiments ofthe present invention and should not be interpreted to limit the scopethereof. The accompanying drawings are not to be considered as drawn toscale unless explicitly noted.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentinvention. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“includes” and/or “including”, when used in this specification, specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

In describing example embodiments shown in the drawings, specificterminology is employed for the sake of clarity. However, the presentdisclosure is not intended to be limited to the specific terminology soselected and it is to be understood that each specific element includesall technical equivalents that operate in a similar manner.

In the following description, illustrative embodiments will be describedwith reference to acts and symbolic representations of operations (e.g.,in the form of flowcharts) that may be implemented as program modules orfunctional processes including routines, programs, objects, components,data structures, etc., that perform particular tasks or implementparticular abstract data types and may be implemented using existinghardware at existing network elements or control nodes. Such existinghardware may include one or more Central Processing Units (CPUs),digital signal processors (DSPs),application-specific-integrated-circuits, field programmable gate arrays(FPGAs) computers or the like. These terms in general may be referred toas processors.

Unless specifically stated otherwise, or as is apparent from thediscussion, terms such as “processing” or “computing” or “calculating”or “determining” or “displaying” or the like, refer to the action andprocesses of a computer system, or similar electronic computing device,that manipulates and transforms data represented as physical, electronicquantities within the computer system's registers and memories intoother data similarly represented as physical quantities within thecomputer system memories or registers or other such information storage,transmission or display devices.

Referring now to FIGS. 1 to 27, an example embodiment of the presentinvention is described.

<Configuration>

FIG. 1 illustrates a configuration of a communication system 1 accordingto an example embodiment of the present invention. The communicationsystem 1 of FIG. 1 includes a plurality of communication terminals 10aa, 10 ab, 10 ac, 10 ba, 10 bb, 10 bc, 10 ca, 10 cb, 10 cc, 10 da, 10db, and 10 dc, and a plurality of displays 120 aa, 120 ab, 120 ac, 120ba, 120 bb, 120 bc, 120 ca, 120 cb, 120 cc, 120 da, 120 db, and 120 dc,a plurality of relay devices 30 a, 30 b, and 30 c, a communicationmanagement system 50, a conversion system 80, a program providing system90, and a maintenance system 100. In the following examples, thecommunication system 1 is implemented as a videoconference system thatallows at least two of the plurality of communication terminals 10 toremotely communicate with one another. More specifically, thecommunication system 1 allows transmission of contents data, such asimage data and sound data, between or among at least two of theplurality of communication terminals 10. The communication system 1further includes a plurality of routers 70 a, 70 b, 70 c, 70 d, 70 ab,and 70 cd, which may be collectively or each referred to as the router70. The router 70 selects a route that is most suitable for transmittingcontents data such as image data and sound data.

Still referring to FIG. 1, the terminals 10 aa, 10 ab, and 10 ac, therelay device 30 a, and the router 70 a are connected to a local areanetwork (LAN) 2 a. The terminals 10 ba, 10 bb, and 10 bc, the relaydevice 30 b, and the router 70 b are connected to a LAN 2 b. The LAN 2 aand the LAN 2 b are connected to a leased line 2 ab in which the router70 ab is provided. It is assumed that the LAN 2 a, LAN 2 b, and theleased line 2 ab, are located in an area X. For example, assuming thatthe area X is any area in Japan, the LAN 2 a could be located within anoffice in a city such as Tokyo, and the LAN 2 b could be located withinan office in another city such as Osaka.

The terminals 10 ca, 10 cb, and 10 cc, the relay device 30 c, and therouter 70 c are connected to a LAN 2 c. The terminals 10 da, 10 db, and10 dc, the relay device 30 d, and the router 70 d are connected to a LAN2 d. The LAN 2 c and the LAN 2 d are connected to a leased line 2 cd inwhich the router 70 cd is provided. It is assumed that the LAN 2 c, LAN2 d, and leased line 2 cd are located in an area Y apart from the areaX. For example, assuming that the area is any area in the United States,the LAN 2 c could be located within an office in a city such as NewYork, and the LAN 2 d could be located within an office in another citysuch as Washington, D.C. The area X and the area Y are connected throughthe Internet 2 i, via the routers 70 ab and 70 cd.

For the descriptive purposes, in this example, any number of theplurality of communication terminals 10 aa to 10 dc may be collectivelyor each referred to as the terminal 10. Any number of the plurality ofdisplays 120 aa to 120 dc may be collectively or each referred to as thedisplay 120. Any number of the plurality of relay devices 30 a, 30 b,and 30 c may be collectively or each referred to as the relay device 30.The communication management system 50 may be referred to as the“management system” 50.

The terminal 10 that transmits data to another terminal 10 to carry outvideoconference is referred to as the request terminal 10. The terminal10 that receives data from another terminal 10 to carry outvideoconference is referred to as the counterpart terminal 10. Forexample, the request terminal 10 includes any terminal 10 that requestsanother terminal 10 to start videoconference, and the counterpartterminal 10 includes any terminal 10 that is requested by the requestterminal 10 to start videoconference.

The management system 50, the program providing system 90, and themaintenance system 100 are connected through the Internet 2 i to theterminal 10 and the relay device 30. In this example, the conversionsystem 80 is connected to the router 70 d on the LAN 2 d, located in thearea Y. Any one of the management system 50, the program providingsystem 90, and the maintenance system 100 may be located at any locationwithin or outside any one of the area X and the area Y.

In this example, the communications network 2 includes the LAN 2 a, LAN2 b, leased line 2 ab, Internet 2 i, leased line 2 cd, LAN 2 c, and LAN2 d. Any one or any portion of these lines or any other lines that maybe included in the communications network 2 may be implemented as wirednetwork or wireless network such as Wireless Fidelity (WiFi) network orBluetooth network.

As shown in FIG. 1, the terminal 10, the relay device 30, the managementsystem 50, the router 70, the conversion system 80, the programproviding system 90, and the maintenance system 100 are each providedwith four digit numbers. These four digit numbers separated by dots arethe simple expressions of IP addresses respectively assigned to any oneof the devices shown in FIG. 1, each of which has a function ofcommunication device. For example, the IP address of the terminal 10 aais “1.2.1.3”. For simplicity, it is assumed that the IP address isexpressed in IPv4. Alternatively, the IP address may be expressed inIPv6.

Further, in this example, the terminal 10 may be communicated in variousways. For example, at least two different terminals 10 that are locatedat different rooms in the same office, or at least two differentterminals 10 that are located at different offices that are remotelylocated from one another, may communicate with one another. In anotherexample, at least two different terminals 10 that are located in thesame room may communicate with one another. In another example, oneterminal 10 that is located indoor and another terminal 10 that islocated outdoor, or at least two different terminals 10 that are bothlocated outdoor, may communicate with one another. When the terminal 10is located outdoor, the terminal 10 communicates with the other terminal10 through a wireless network such as a wireless network designed for amobile phone.

The communication terminal 10 of FIG. 1 allows a user to communicatewith another user at the counterpart communication terminal 10, bytransmitting or receiving contents data such as image data and sounddata. For example, any terminal that may be used for videoconference maybe used. Further, the terminal 10 transmits or receives contents data toor from the counterpart terminal 10 using a predetermined communicationsprotocol. The communications protocol used by the terminal 10 is mainlydefined by a call control protocol used for connecting or disconnectingconnections with the counterpart terminal, and an encoding format usedfor encoding the contents data to an IP packet.

Examples of the call control protocol being used by the terminal 10include, but not limited to, (1) session initial protocol (SIP), (2)H.323, (3) the extended SIP, (4) Instant Messenger (IM) Protocol such asextensible messaging and presence protocol (XMPP), ICQ (RegisteredTrademark), AIM (Registered Trademark), or Skype (Registered Trademark),(5) protocol using the SIP message method, (6) Internet relay chat (IRC)protocol, and (7) extended IM based protocol such as Jingle.

Further, in this example, any one of the communication terminal 10 thatcommunicates data using a predetermined communications protocol, isreferred to as a dedicated terminal 10A. In one example, the dedicatedterminal 10A uses the (4) IM protocol or the (7) extended IM basedprotocol as a call control protocol, and the Scalable Video Coding (SVC)as an encoding format. The SVC is the Annex G extension of the AGC.

Further, any one of the communication terminal 10 that communicates datausing a communications protocol other than the predeterminedcommunications protocol of the dedicated terminal 10A, is referred to asa non-dedicated terminal 10D. In this example, when the communicationterminal 10 uses a call control protocol other than the (4) IM protocolor the (7) extended IM based protocol, and/or an encoding format otherthan the SVC, it is determined that the communication terminal 10 is thenon-dedicated terminal 10D.

In one example, whether the terminal 10 is the dedicated terminal 10A orthe non-dedicated terminal 10D may depend on a specific organizationthat manufactures, sells, or manages the terminal 10, as thecommunications protocol may be determined based on a communicationsnetwork or system in use by the specific organization. The dedicatedterminal 10A is defined as a communication terminal that ismanufactured, sold, or managed by a specific organization such as aspecific company. The non-dedicated terminal 10D is defined as acommunication terminal that is manufactured, sold, or managed by anorganization other than the specific organization.

In another example, whether the terminal 10 is the dedicated terminal10A or the non-dedicated terminal 10D may depend on time when theterminal 10 is manufactured, or time when the terminal 10 is sold suchas when it is released to the market. The dedicated terminal 10A may bedefined as a communication terminal that is manufactured or sold by aspecific organization, after the time when the non-dedicated terminal10D is manufactured or sold by the specific organization. For example,even though the dedicated terminal 10A and the non-dedicated terminal10D are both manufactured, sold, or managed by the same organization,the dedicated terminal 10A may be a new model such that it communicatesusing a different communications protocol than the communicationsprotocol of the non-dedicated terminal 10D.

The relay device 30 is a computer system, which may be implemented byone or more computers, to relay contents data between or among theterminals 10. The management system 50 is a computer system, which maybe implemented by one or more computers, to centrally manage variousinformation such as login information of the terminal 10, thecommunication state of the terminal 10, candidate list information, andthe communication state of the relay device 30. In this example, amoving image, a still image, or both of the still image and the movingimage, may be transmitted as the image data.

The conversion system 80 functions as a signaling gateway that convertsa call control signal as well as a video/audio gateway that encodes thecontents data. More specifically, the conversion system 80 converts acommunications protocol of the contents data that is transmitted fromone terminal 10, to a communications protocol compatible with the othercounterpart terminal 10. The conversion system 80 at least converts acall control protocol or an encoding format of the contents data so thatthe contents data is compatible with the terminal 10 to which thecontents data is sent.

The program providing system 90 is a computer system, which may beimplemented by one or more computers, to provide programs to theterminal 10, the relay device 30, the management system 50, theconversion system 80, and the maintenance system 100, respectively,through the communications network 2.

The maintenance system 100 is a computer system, which may beimplemented by one or more computers, to maintain, manage, fix, orupgrade at least one of the terminal 10, relay device 30, managementsystem 50, conversion system 80, and program providing system 90.Assuming that the maintenance system 100 is provided within a country,and the terminal 10, relay device 30, management system 50, conversionsystem 80, and program providing system 90 are each installed outsidethe country, the maintenance system 100 maintains, manages, fixes, orupgrades at least one of the terminal 10, relay device 30, managementsystem 50, conversion system 80, and program providing system 90,remotely through the communications network 2. The maintenance system100 may manage maintenance of at least one of the terminal 10, relaydevice 30, management system 50, conversion system 80, and programproviding system 90 without using the communications network 2. Forexample, a machine type number, a manufacturing number, customerinformation, maintenance and repair information, and failure loginformation may be maintained at the maintenance system 100 withoutusing the communications network 2.

Referring now to FIGS. 2 and 3A to 3C, a first communications pattern inwhich contents data are transmitted between two dedicated terminals 10Ais explained according to an example embodiment of the presentinvention. FIG. 2 illustrates a communication state in which thecommunication terminals 10 communicate with each other using the samecommunications protocol.

As illustrated in FIG. 2, in the first communications pattern, thecommunication terminals 10 in the communication system 1 communicatewith each other in compliance with the H.264/SVC video coding standards.More specifically, in the communication system 1, the request terminal10 and the counterpart terminal 10 each of which is implemented as thededicated terminal 10A establish a management data communication session“sei” through the management system 50 to transmit or receive variousmanagement data “M”. The request terminal 10 and the counterpartterminal 10 further establish four contents data communication sessionsincluding a session “HL” to transmit high-level resolution image data, asession “ML” to transmit medium-level resolution image data, a session“LL” to transmit low-level resolution image data, and a session “V” totransmit sound data, through the relay device 30.

Referring to FIG. 2, the above-described four contents datacommunication sessions established between the request terminal 10 andthe relay device 30 to transmit contents data are collectively referredto as a first communication session “sed1”. The above-described fourcontents data communication sessions established between the counterpartterminal 10 and the relay device 30 to transmit contents data arecollectively referred to as a second communication session “sed2”.

Referring now to FIGS. 3A to 3C, resolution of image data to betransmitted or received according to the first communications pattern ofFIG. 2, in compliance with the SVC standards, is explained in moredetail.

As illustrated in FIG. 3A, the low-level resolution image data, whichfunctions as a base image, has 160 pixels in the horizontal directionand 120 pixels in the vertical direction. Referring to FIG. 3B, themedium-level resolution image data has 320 pixels in the horizontaldirection and 240 pixels in the vertical direction. Referring to FIG.3C, the high-level resolution image data has 640 pixels in thehorizontal direction and 480 pixels in the vertical direction. In caseof communicating with a narrowband signal line, low-quality image datathat is generated based on the low-level resolution image data, which isthe base image, is transmitted. In case of communicating with a widebandsignal line, medium-quality image data that is generated based on thelow-level resolution image data and the medium-level resolution imagedata is transmitted. In case of communicating with a broadband signalline, high-quality image data that is generated based on the low-levelresolution image data, the medium-level resolution image data, and thehigh-level resolution image data is transmitted. Any one of theabove-described types of image data may be transmitted together withsound data such as voice data.

Referring now to FIGS. 4 and 5, a second communications pattern in whichcontents data are transmitted between the dedicated terminal 10A and thenon-dedicated terminal 10D is explained according to an exampleembodiment of the present invention. FIG. 4 illustrates a communicationstate in which the communication terminals 10 communicate with eachother using different communications protocols.

As illustrated in FIG. 4, in the second communications pattern, onecommunication terminal 10 in the communication system 1 communicates incompliance with the H.264/SVC video coding standards, and the othercommunication terminal 10 in the communication system 1 communicates incompliance with the H.264/advanced video coding (AVC) video codingstandards. More specifically, in the communication system 1, the requestterminal 10 that is implemented as the dedicated terminal 10A, and thecounterpart terminal 10 that is implemented as the non-dedicatedterminal 10D, establish a management data communication session “sei1”through the management system 50 to transmit or receive variousmanagement data “M”. More specifically, in this example, the managementdata communication session “sei1” is established between the dedicatedterminal 10A and the non-dedicated terminal 10D through the managementsystem 50, via the relay device 30 and the conversion system 80. Themanagement system 50 and the conversion system 80 establish a managementdata communication session “sei2” to transmit or receive variousmanagement data.

The request terminal 10A and the conversion system 80 establish fourcontents data communication sessions including a session “HL” totransmit high-level resolution image data, a session “ML” to transmitmedium-level resolution image data, a session “LL” to transmit low-levelresolution image data, and a session “V” to transmit sound data, throughthe relay device 30, based on the H.264/SVC standards. In FIG. 4, theabove-described four contents data communication sessions establishedbetween the request terminal 10A and the relay device 30 to transmitcontents data are collectively referred to as a first communicationsession “sed11”. The above-described four contents data communicationsessions established between the conversion system 80 and the relaydevice 30 to transmit contents data are collectively referred to as asecond communication session “sed12”.

The conversion system 80 and the counterpart terminal 10D establish twocontents data communication sessions including a session “ML” totransmit medium-level resolution image data, and a session “V” totransmit sound data, through the relay device 30, based on the H.264/AVCstandards. In FIG. 4, the above-described two contents datacommunication sessions established between the conversion system 80 andthe counterpart terminal 10D to transmit contents data are collectivelyreferred to as a third communication session “sed13”.

Referring now to FIGS. 3A to 3C and 5, resolution of image data to betransmitted or received according to the second communications patternof FIG. 4, in compliance with the AVC standards, is explained in moredetail.

In the first communication session “sed11” and the second communicationsession “sed12” of FIG. 4, the low-level resolution image data of FIG.3A, the medium-level resolution image data of FIG. 3B, and thehigh-level resolution image data of FIG. 3C may be transmitted orreceived, as described above referring to the example case of FIG. 2. Inthe third communication session “sed13” of FIG. 4, the medium-levelresolution image data of FIG. 5 is transmitted or received. Themedium-level resolution image data of FIG. 5 is substantially similar tothe medium-level resolution image data of FIG. 3B. Any one of theabove-described types of image data may be transmitted together withsound data such as voice data.

<Hardware Structure of Communication System>

FIG. 6 is a perspective view illustrating the outer appearance of thecommunication terminal 10 of the communication system 1 of FIG. 1. Asillustrated in FIG. 6, the terminal 10 includes a body 1100, an arm1200, and a camera housing 1300. The body 1100 includes a front sidewall 1110 having a plurality of air intake holes that are formed overthe nearly entire surface of the intake surface of the front side wall1110. The body 1100 further includes a back side wall 1120 provided withan exhaust surface 1121 having a plurality of exhaust holes over thenearly entire surface of the exhaust surface 1121. When a cooling fanthat is provided within the body 1100 is driven, air flows in throughthe intake holes of the intake surface and out through the exhaust holesof the exhaust surface 1121. The body 1100 further includes a right sidewall 1130 formed with a sound pickup hole 1131. Through the sound pickuphole 1131, a microphone 114 (FIG. 7) of the terminal 10 is able to catchsounds such as human voice or any sound including noise.

The body 1100 has an operation panel 1150, which is provided at a frontsurface toward the right side wall 1130. The operation panel 1150includes a plurality of operation keys 108 a to 108 e (“the operationkey 108”), a power switch 109, an alarm lamp 119, and a plurality ofsound output holes 1151. Through the sound output holes 1151, a speaker115 (FIG. 7) of the terminal 10 is able to output sounds such as soundsgenerated based on human voice. The body 1100 further includes a holder1160, which is provided at the front surface toward the left side wall1140. The holder 1160, which has a concave shape, accommodates thereinthe arm 1200 and the camera housing 1300. The right side wall 1130 isfurther provided with a plurality of connection ports 1132 a to 1132 c(“connection ports 1132”). The connection ports 1132 allow electricalconnection to an external device through an outside device connectionI/F 118 (FIG. 7). The body 1100 further includes a left side wall 1140,which is provided with a connection port to connect the external display120 to the display I/F 117 through a cable 120 c.

The arm 1200 is fixed to the body 1100 via a torque hinge 1210. With thetorque hinge 1210, the arm 1200 can be rotated in directions of up anddown with respect to the body, while making a tilt angle θ1 of up to 135degrees. FIG. 6 illustrates the case where the tilt angle θ1 is 90degrees.

The camera housing 1300 incorporates therein the camera 112 (FIG. 7)that takes an image of an object. The object may be a part of a user,document, or a room where the terminal 10 is located. The camera housing1300 is provided with a torque hinge 1310. The camera housing 1300 isfixed to the arm 1200 through the torque hinge 1310. With the torquehinge 1310, the camera housing 1300 can be rotated with respect to thearm 1200, in the direction of up, down, right, and left, such that thecamera housing 1300 is kept at a desired position. More specifically,the camera housing 1300 can be rotated, while making a pan angle θ2 fromabout −180 degrees to 180 degrees in the direction right and left, and atilt angle θ3 that ranges from about −45 degrees to +45 degrees in thedirection of up and down. In FIG. 6, the pan angle θ2 and the tilt angleθ3 are each 0 degree.

The relay device 30, the management system 50, the conversion system 80,the program providing system 90, and the maintenance system 100 are eachimplemented by any desired number of general-purpose computers such as apersonal computer or a server computer. For simplicity, explanation ofthe outer appearance of the computer is omitted.

FIG. 7 is a schematic block diagram illustrating a hardware structure ofthe communication terminal 10. As illustrated in FIG. 7, the terminal 10includes a central processing unit (CPU) 101, a read only memory (ROM)102, a random access memory (RAM) 103, a flash memory 104, a solid statedrive (SSD) 105, a medium drive 107, the operation key 108, the powerswitch 109, a network interface (I/F) 111, the camera 112, an imagingelement interface (I/F) 113, the microphone 114, the speaker 115, asound input/output interface (I/O I/F) 116, the display interface (I/F)117, the outside device connection interface (I/F) 118, and an alarmlamp 119, which are electrically connected through a bus 110 such as anaddress bus or data bus. The CPU 101 controls entire operation of theterminal 10. The ROM 102 stores therein a control program for executionby the CPU 101, such as an initial program loader (IPL). The RAM 103functions as a work area of the CPU 101. The flash memory 104 storestherein various data such as the terminal control program, image data,or sound data such as voice data. The SSD 105 controls reading orwriting of various data with respect to the flash memory 104 undercontrol of the CPU 101. The medium drive 107 controls reading or writingof various data with respect to a removable recording medium 106 such asa flash memory. The operation key 108 allows the user to input a userinstruction, for example, by allowing the user to select a communicationdestination such as the counterpart terminal 10. The power switch 109allows the user to switch on or off the power of the terminal 10. Thenetwork I/F 111 allows the terminal 10 to transmit data through thecommunications network 2.

The camera 112 takes an image of an object to obtain image data undercontrol of the CPU 101. The imaging element I/F 113 controls operationof the camera 112. The microphone 114 catches sounds such as voice ofthe user at the terminal 10. The speaker 115 outputs sounds such assounds generated based on voice of the user at the counterpart terminal10. The sound I/O I/F 116 controls input or output of sound signals suchas voice signals with respect to the microphone 114 and the speaker 115under control of the CPU 101. The display I/F 117 transmits image datato the display 120 under control of the CPU 101. The outside deviceconnection I/F 118 controls connection of the terminal 10 to varioustypes of outside device. The alarm lamp 119 generates notification whenan error is detected in the terminal 10.

The display 120 may be implemented by a liquid crystal display (LCD) oran organic light emitting display, which displays various data such asan image of an object or an operation icon. As illustrated in FIGS. 6and 7, the display 120 is connected to the display I/F 117 through thecable 120 c. The cable 120 c may be implemented by an analog RCB (VGA)signal cable, a component video cable, a high-definition multimediainterface (HDMI) signal cable, or a digital video interactive (DVI)signal cable.

The camera 112 includes a plurality of devices such as a lens system,and a solid-state image sensing device that photo-electrically convertsa light to generate an image of an object. For example, the solid-stateimage sensing device includes a complementary metal oxide semiconductor(CMOS) or a charge coupled device (CCD).

The outside device connection I/F 118 may be connected to an outsidedevice such as an external camera, external microphone, or externalspeaker through a universal serial bus (USB) cable that is connectedthrough the port 1132 of the body 1100 (FIG. 6). When the externalcamera is connected to the terminal 10, the CPU 101 causes the terminal10 to capture an image using the external camera, rather than the camera112 that is incorporated in the terminal 10. When the externalmicrophone or the external speaker is connected to the terminal 10, theCPU 101 causes the terminal 10 to use the external microphone or theexternal speaker in replace of the incorporated microphone 114 or theincorporated speaker 115.

The recording medium 106, which can be freely attached to or detachedfrom the terminal 10, includes any desired type of recording medium. Inalternative to the flash memory 104, any nonvolatile memory that isreadable and writable under control of the CPU 101 may be used such asElectrically Erasable and Programmable ROM (EEPROM).

The terminal control program may be written onto a recording medium thatis readable by a general-purpose computer such as the recording medium106 in any format that is installable or executable by a general-purposecomputer. Once the terminal control program is written onto therecording medium, the recording medium may be distributed. Further, theterminal control program may be stored in any desired memory other thanthe flash memory 104, such as the ROM 102.

FIG. 8 illustrates a hardware structure of the management system 50 ofFIG. 1. The management system 50 includes a CPU 201, a ROM 202, a RAM203, the HD 204, a hard disk drive (HDD) 205, a medium drive 207, adisplay 208, a network interface (I/F) 209, a keyboard 211, a mouse 212,and a CD-ROM drive 214, which are electrically connected through a bus210 such as an address bus or a data bus.

The CPU 201 controls entire operation of the management system 50. TheROM 202 stores a control program for execution by the CPU 201, such asan IPL. The RAM 203 functions as a work area of the CPU 201. The HD 204stores therein various data such as the transmission management program.The HDD 205 controls reading or writing of various data with respect tothe HD 204 under control of the CPU 201. The medium drive 207 controlsreading or writing of various data with respect to a removable recordingmedium 206 such as a flash memory. The display 208 displays various datasuch as a cursor, menu, window, character, or image. The network I/F 209allows the management system 50 to transmit data through thecommunications network 2. The keyboard 211 includes a plurality of keys,each of which is used for inputting a user instruction through acharacter, a numeral, or a symbol. The mouse 212 allows the user toinput a user instruction including, for example, selection or executionof a specific instruction, selection of an area to be processed, andinstruction of cursor movement. The CD-ROM drive 214 controls reading orwriting of various data with respect to a CD-ROM 213. In alternative tothe CD-ROM 213, any removable recording medium may be used.

The communication management program may be written onto a recordingmedium that is readable by a general-purpose computer such as therecording medium 206 or the CD-ROM 213 in any format that is installableor executable by a general-purpose computer. Once the communicationmanagement program is written onto the recording medium, the recordingmedium may be distributed. Further, the communication management programmay be stored in any desired memory other than the HD 204, such as theROM 202.

The relay device 30 is substantially similar in hardware structure tothe management system 50 of FIG. 8, except for replacement of themanagement program with a relay device control program that is used forcontrolling the relay device 30. The relay device control program may bewritten onto a recording medium that is readable by a general-purposecomputer such as the recording medium 206 or the CD-ROM 213 in anyformat that is installable or executable by the general-purposecomputer. Once the relay device control program is written onto therecording medium, the recording medium may be distributed. Further, therelay device control program may be stored in any desired memory otherthan the HD 204, such as the ROM 202.

The conversion system 80 is substantially similar in hardware structureto the management system 50 of FIG. 8, except for replacement of themanagement program with a conversion control program that is used forcontrolling the conversion system 80. The conversion control program maybe written onto a recording medium that is readable by a general-purposecomputer such as the recording medium 206 or the CD-ROM 213 in anyformat that is installable or executable by the general-purposecomputer. Once the conversion control program is written onto therecording medium, the recording medium may be distributed. Further, theconversion control program may be stored in any desired memory otherthan the HD 204, such as the ROM 202.

The program providing system 90 is substantially similar in hardwarestructure to the management system 50 of FIG. 8, except for replacementof the management program with a program providing program that is usedfor controlling the program providing system 90. The program providingprogram may be written onto a recording medium that is readable by ageneral-purpose computer such as the recording medium 206 or the CD-ROM213 in any format that is installable or executable by thegeneral-purpose computer. Once the program providing program is writtenonto the recording medium, the recording medium may be distributed.Further, the program providing program may be stored in any desiredmemory other than the HD 204, such as the ROM 202.

The maintenance system 100 is substantially similar in hardwarestructure to the management system 50 of FIG. 8, except for replacementof the management program with a maintenance program that is used forcontrolling the maintenance system 100. The maintenance program may bewritten onto a recording medium that is readable by a general-purposecomputer such as the recording medium 206 or the CD-ROM 213 in anyformat that is installable or executable by the general-purposecomputer. Once the maintenance program is written onto the recordingmedium, the recording medium may be distributed. Further, themaintenance program may be stored in any desired memory other than theHD 204, such as the ROM 202.

Other examples of removable recording medium, which may be used inreplace of the CD-ROM 213, include, but not limited to, compact discrecordable (CD-R), digital versatile disk (DVD), and blue ray disc.

<Functional Structure of Communication System>

Next, a functional structure of the communication system of FIG. 1 isexplained according to an example embodiment of the present invention.FIG. 9 is a schematic block diagram illustrating functional structure ofthe communication system 1. As illustrated in FIG. 9, the terminal 10,the relay device 30, the management system 50, and the conversion system80 exchange data with one another through the communications network 2.In FIG. 9, the program providing system 90 and the maintenance system100 of FIG. 1 are omitted.

<Functional Structure of Terminal>

The terminal 10 includes a data transmitter/receiver 11, an operationinput 12, a login request 13, an imaging unit 14, a sound input 15 a, asound output 15 b, a display control 16, a delay detector 17, and amemory control 19. These units shown in FIG. 9 correspond to a pluralityof functions or functional modules, which are executed according to aninstruction of the CPU 101 (FIG. 7) that is generated according to theterminal control program being loaded from the flash memory 104 onto theRAM 103. The terminal 10 further includes a memory 1000 that may beimplemented by the flash memory 104 and the RAM 103 of FIG. 7.

Referring now to FIGS. 7 and 9, a functional structure of the terminal10 is explained according to an example embodiment of the presentinvention. More specifically, in this example, the operations orfunctions that are performed by the terminal 10, which include theoperations or functions performed by the units shown in FIG. 9, areperformed in cooperation with one or more hardware devices of theterminal 10 that are shown in FIG. 7.

The data transmitter/receiver 11, which may be implemented by thenetwork I/F 111 (FIG. 7) under control of the CPU 101, transmits orreceives various data or information to or from another terminal,device, or system, through the communications network 2. In thisexample, the data transmitter/receiver 11 starts receiving the operationstate information that indicates the operation state of each candidatecounterpart terminal 10 from the management system 50, before startingcommunication with any counterpart terminal 10. The operation state ofthe candidate terminal 10 indicates whether the candidate terminal 10 isonline or offline. When the terminal 10 is online, the operation stateof the candidate terminal 10 further indicates whether the candidateterminal 10 is available for communication (“communication OK”), thecandidate terminal 10 is having communication with the other terminal(“communicating”), the candidate terminal 10 is not available as theuser leaves the seat, or the candidate terminal 10 is havingcommunication but interrupted (“communication, interrupted). Theoperation state of the candidate terminal 10 may further indicatewhether the candidate terminal 10 is online but in trouble or error(“online, communicating, trouble”), the candidate terminal 10 is onlinebut not capable of outputting image data such that only sound data isoutput, or the candidate terminal 10 is online but in mute state(“online, mute”) such that sound data is not output. For example, whenthe cable 120 c is disconnected from the terminal 10, the operationstate of the candidate terminal 10 is assumed to be in the troublestate. For the descriptive purposes, in the following examples, it isassumed that the operation state information indicates whether thecandidate terminal 10 is online or offline, and if online, whether thecandidate terminal 10 is available for communication, for example, asdescribed above referring to FIG. 10.

The operation input 12 receives a user instruction input by the userthrough the operation key 108 or the power switch 109 (FIG. 7), undercontrol of the instructions received from the CPU 101. For example, whenthe user selects “ON” using the power switch 109, the operation input 12receives a user instruction for turning the power on, and causes theterminal 10 to turn on the power.

The operations or functions of the login request 13 are performedaccording to an instruction received from the CPU 101 (FIG. 7). When thepower of the terminal 10 is turned on, the login request 13automatically causes the data transmitter/receiver 11 to send loginrequest information that requests the login process, and a current IPaddress of the terminal 10, to the management system 50 through thecommunications network 2. When the power of the terminal 10 is turnedoff according to a user instruction received from the user through thepower switch 109, the login request 13 causes the datatransmitter/receiver 11 to send current operation state information ofthe terminal 10 to the management system 50, which indicates that thepower of the terminal 10 is turned off. After the operation stateinformation is sent, the operation input 12 turns off the power of theterminal 10. As the operation state information of the terminal 10 issent every time the power is turned off, the management system 50 isable to know that the terminal 10 is offline in realtime.

The operations or functions of the imaging unit 14 of the terminal 10are performed by the camera 112 and the imaging element I/F 113according to an instruction received from the CPU 101 (FIG. 7). Theimaging unit 14 takes an image of an object to output image data of theobject.

The operations or functions of the sound input 15 a of the terminal 10are performed by the sound I/O I/F 116 according to an instructionreceived from the CPU 101, in cooperation with the microphone 114. Afterthe microphone 114 converts sounds of the user at the terminal 10 to asound signal, the sound input 15 a inputs the sound signal in the formof sound data for further processing. The operations or functions of thesound output 15 b of the terminal 10 are performed by the sound I/O I/F116 according to an instruction received from the CPU 101, incooperation with the speaker 115. The sound output 15 b outputs a soundsignal of sound data that is received from the counterpart terminal 10through the speaker 115.

The operations or functions of the display control 16 of the terminal 10of FIG. 9 are performed by the display I/F 117 according to aninstruction received from the CPU 101 (FIG. 7). The display control 16controls transmit of image data, which is generated based on image dataof different resolutions, to the display 120. The display control 16further causes the display 120 that is provided for the request terminal10 to display a candidate list before the request terminal 10 startsvideoconference with a desired counterpart terminal 10.

The delay detector 17 detects a delay time ms indicating a time periodin which contents data such as image data or sound data sent through therelay device 30 from another terminal 10 is delayed, according to aninstruction received from the CPU 101 (FIG. 7).

The memory control 19 is implemented by the SSD 105 of FIG. 7 accordingto an instruction received from the CPU 101. The memory control 19stores various data in the memory 1000, or reads out various data fromthe memory 1000. The memory 1000 stores therein various data such asterminal identification (ID) information for identifying the terminal10, and a password for authenticating a user at the terminal 10. Thememory 1000 further stores therein image data and/or sound data that isreceived as the terminal 10 communicates with a counterpart terminal 10such that the image data and/or sound data are overwritten. Before theimage data is overwritten, an image generated based on the image data isdisplayed onto the display 120. Before the sound data is output, soundsgenerated based on the sound data is output through the speaker 150.

In this example, any one of the terminal ID of the terminal 10 and therelay device ID of the relay device 30 includes any type ofidentification information that can be expressed by any language,character, symbol, mark, or any combination of language, character,symbol, and mark.

<Functional Structure of Relay Device>

Now, a functional structure of the relay device 30 is explained. Therelay device 30 includes a data transmitter/receiver 31, a statedetector 32, a data quality checker 33, a data quality manager 34, adata quality changer 35, and a memory control 39. These units shown inFIG. 9 correspond to a plurality of functions or functional modules,which are executed according to an instruction of the CPU 201 (FIG. 8)that is generated according to the relay device control program beingloaded from the HD 204 onto the RAM 203. The relay device 30 furtherincludes a memory 3000 that may be implemented by the RAM 203 and/or theHD 204 (FIG. 8).

(Data Quality Management Table)

The memory 3000 includes a data quality management database (DB) 3001,which stores a data quality management table illustrated in FIG. 10. Thedata quality management table of FIG. 10 stores an Internet protocol(IP) address of the counterpart terminal 10 to which image data istransmitted through the relay device 30, in association with quality ofimage data to be transmitted through the relay device 30 to thecounterpart terminal 10.

(Functional Structure of Relay Device)

Next, a functional structure of the relay device 30 is explainedaccording to an example embodiment of the present invention. Morespecifically, in this example, the operations or functions that areperformed by the relay device 30, which include the operations orfunctions performed by the units shown in FIG. 9, are performed incooperation with one or more hardware devices of the relay device 30that are shown in FIG. 8.

The data transmitter/receiver 31, which may be implemented by thenetwork I/F 209 (FIG. 8), transmits or receives various data orinformation to or from another terminal, device, or system, through thecommunications network 2, under control of instructions received fromthe CPU 201. Further, the data transmitter/receiver 31 initializes acommunication session for the relay device 30.

More specifically, the data transmitter/receiver 31 transmits sessionstart request information, which instructs to start a communicationsession (the first communication session), to the terminal 10 having theIP address that is received at the data transmitter/receiver 31. Thedata transmitter/receiver 31 transmits session start requestinformation, which instructs to start a communication session (thesecond communication session), to the conversion system 80 having the IPaddress that is received at the data transmitter/receiver 31. The datatransmitter/receiver 31 further transmits the IP address of thecounterpart terminal 10 to the conversion system 80.

The state detector 32, which is implemented by the CPU 201 of FIG. 8,detects an operation state of the relay device 30. For example, theoperation state includes the online state (“online”), the offline state(“offline”), the communicating state (“communicating”), and theinterrupted state (“interrupted”). The online state is a state in whichthe relay terminal 30 is turned on and available for datatransmission/reception. The offline state is a state in which the relayterminal 30 is not available for data transmission/reception, forexample, as the power is not turned on.

The data quality checker 33, which is implemented by the CPU 201 of FIG.8, searches the data quality management DB 3001 (FIG. 10) using the IPaddress of the counterpart terminal 10 as a search key to extractinformation regarding the quality of image data suitable tocommunication with the counterpart terminal 10. Based on the extractedinformation regarding the quality of image data, the relay device 30determines the quality of image data to be transmitted to thecounterpart terminal 10.

The data quality manager 34, which may be implemented by the CPU 201 ofFIG. 8, changes the contents of the data quality management DB 3001based on the quality information that is received from the managementsystem 50. For example, assuming that the request terminal 10 aa havingthe terminal ID “01aa” communicates with the counterpart terminal 10 bahaving the terminal ID “01ba” to transmit or receive high quality imagedata during videoconference, transmission of image data may delay forvarious reasons. For example, if a request terminal 10 bb and acounterpart terminal 10 ca start videoconference over the communicationsnetwork 2, transmission of image data from the request terminal 10 aa tothe counterpart terminal 10 ba tends to slow down due to the increase intraffic. In such case, the relay device 30 changes the quality of imagedata to be transmitted from high image quality to lower image quality.More specifically, the contents in the data quality management DB 3001is changed from high-level image quality to medium-level image quality,based on the quality information indicating the use of medium-levelimage quality.

The data quality changer 35, which may be implemented by the CPU 201 ofFIG. 8, changes the quality of image data received from the requestterminal 10 to the quality of image data according to the contents ofthe data quality management DB 3001.

The memory control 39 is implemented by the HDD 205 of FIG. 8 accordingto an instruction received from the CPU 201. The memory control 39stores various data in the memory 3000, or reads out various data fromthe memory 3000.

<Functional Structure of Management System>

The management system 50 includes a data transmitter/receiver 51, aterminal authenticator 52, a state manager 53, a determiner 55, asession manager 56, a quality determiner 57, a delay time manager 58,and a memory control 59. These units shown in FIG. 9 correspond to aplurality of functions or functional modules, which are executedaccording to an instruction of the CPU 201 (FIG. 8) that is generatedaccording to the transmission management program being loaded from theHD 204 onto the RAM 203. The management system 50 further includes amemory 5000, which may be implemented by the HD 204 (FIG. 8). The memory500 stores various databases, and candidate list frame data.

(Relay Device Management Table)

The memory 5000 includes a relay device management database (DB) 5001,which stores therein a relay device management table of FIG. 11. Therelay device management table of FIG. 11 stores, for each relay deviceID of the relay device 30, the operation state of the relay device 30,the received date and time at which the management system 50 receivesthe operation state information indicating the operation state of therelay device 30 from the relay device 30, the IP address of the relaydevice 30, and the maximum data transmission speed of the relay device30 in Mbps. For example, for the relay device 30 a having the relayterminal ID “111a”, the relay device management table of FIG. 11indicates that the operation state is “ON LINE”, the received date andtime at which the management system 50 receives the operation stateinformation is “13:00 PM of Nov. 10, 2011”, the IP address of the relaydevice 30 a is “1.2.1.2”, and the maximum data transmission speed of therelay terminal 30 a is 100 Mbps.

(Terminal Information Management Table)

The memory 5000 further includes a terminal information managementdatabase (DB) 5002, which stores a terminal information management tableof FIG. 12. The terminal information management table of FIG. 12 storesa plurality of terminal IDs respectively assigned to the terminals 10that are managed by the management system 50, in association with aplurality of passwords that are previously determined for the respectiveterminals 10. The terminal information management table of FIG. 12further stores a model number of the terminal 10, a serial number of theterminal 10, and a communications protocol of the terminal 10, for eachone of the terminals 10. The terminal information management table ofFIG. 12 further stores an IP address for the non-dedicated terminal 10D.For example, referring to the terminal information management table ofFIG. 12, the terminal 10 da having the terminal ID “01da” is assignedwith the password “dada”, and has the model number “8001”, the serialnumber “1001”, the communications protocol “non-dedicated 1”, and the IPaddress “1.3.2.3”. While the IP address of the non-dedicated terminal10D is managed using the terminal information management table of FIG.12 as static data, the IP address of the dedicated terminal 10A ismanaged using a terminal state management table of FIG. 13 as dynamicdata. The dedicated terminal 10A is capable of changing its IP address,which may be convenient.

In this example, the communications protocol “dedicated” indicates thatthe terminal 10 uses the communications protocol used by the dedicatedterminal 10A as described above referring to FIGS. 2 and 4. Thecommunications protocol “non-dedicated 1” indicates that the terminal 10uses the communications protocol used by the non-dedicated terminal 10Das described above referring to FIG. 4. The communications protocol“non-dedicated 2” indicates that the terminal 10 uses a communicationsprotocol, which differs from the communications protocol used by thededicated terminal 10A and the communications protocol used by thenon-dedicated terminal 10D. In other words, the non-dedicated terminal10D may not only be limited to one type of communication terminal 10.

(Terminal State Management Table)

The memory 5000 further includes a terminal state management database(DB) 5003, which stores the terminal state management table of FIG. 13.The terminal state management table of FIG. 13 stores, for each one ofthe terminal IDs assigned to the terminals 10, the terminal name to beused for communication with the terminal 10, the terminal name of theterminal 10, the operation state of the terminal 10, the received dateand time at which the management system 50 receives the login requestinformation from the terminal 10, and the IP address of the terminal 10.For example, for the terminal 10 aa having the terminal ID “01aa”, theterminal state management table of FIG. 13 indicates that the terminalname is “Japan Tokyo Office AA terminal”, the operation state is online(“ONLINE”) and is available for communication (“COMMUNICATION OK”), thereceived date and time is “13:40 PM, Nov. 10, 2011”, and the IP addressof the terminal 10 aa is “1.2.1.3”.

In this example, the terminal state management table of FIG. 13 onlymanages information regarding the dedicated terminals 10A such thatinformation regarding any terminal other than the dedicated terminals10A, such as the IP addresses of the non-dedicated terminals 10D, arenot managed using the terminal state management table of FIG. 13.

(Candidate List Management Table)

The memory 5000 further includes a candidate list management database(DB) 5004, which stores a candidate list management table of FIG. 14.The candidate list management table of FIG. 14 stores, for each one of aplurality of request terminals 10 capable of requesting forvideoconference communication, the terminal ID of the request terminal10, and one or more terminal IDs that are respectively assigned tocandidate terminals 10 that are previously registered for the requestterminal 10. In this example, for the request terminal 10, one or moreterminals 10 of the communication system 1 of FIG. 1 are previouslyregistered as the candidate terminal 10. For example, the candidate listmanagement table of FIG. 14 indicates that the request terminal 10 aahaving the terminal ID “01aa” is most likely to request forvideoconference with respect to the terminal 10 ab having the terminalID “01ab”, the terminal 10 ba having the terminal ID “01ba”, and theterminal 10 bb having the terminal ID “01bb”, etc. The management system50 manages the candidate list management table of FIG. 14, for example,according to a user instruction received from any one of the terminals10. For example, in response to a user instruction received from theterminal 10 aa, the management system 50 may add or delete the contentsof the candidate list management table of FIG. 14.

As described above, the terminal state management table of FIG. 13 doesnot store information such as the IP address regarding the terminal 10other than the dedicated terminal 10A. The candidate list managementtable of FIG. 14 stores information such as the terminal ID regardingthe terminal 10 other than the dedicated terminal 10A. Morespecifically, the candidate list management table of FIG. 14 storesinformation regarding the candidate counterpart terminal 10 irrespectiveof whether the terminal 10 is the dedicated terminal 10A or thenon-dedicated terminal 10D.

(Session Management Table)

The memory 5000 further includes a session management database (DB)5005, which stores a session management table of FIG. 15. The sessionmanagement table of FIG. 15 stores information regarding each of thesessions that are carried out by at least two terminals 10 of thecommunication system 1. The information of the session management tableof FIG. 15 may be used for the purpose of selecting the relay device 30that is most suitable for communication between at least two terminals10. More specifically, for each session, the session management table ofFIG. 15 stores a session ID that identifies the session, a relay deviceID of the relay device 30 to be used for transmitting or receivingcontents data such as image data and sound data, a terminal ID of therequest terminal 10, a terminal ID of the counterpart terminal 10, adelay time ms indicating a time period required for receiving contentsdata at the counterpart terminal 10, and the date and time informationindicating the time at which the management system 50 receives delayinformation from the counterpart terminal 10.

For example, referring to the session management table of FIG. 15, therelay device 30 a having the relay device ID “111a” is selected to relayimage data and sound data between the request terminal 10 aa having theterminal ID “01aa” and the counterpart terminal 10 ca having theterminal ID “01ca”. Further, the management system 50 receives the delayinformation from the counterpart terminal 10 ca at 14:00 PM, Nov. 10,2011. Based on the delay information, the delay time ms of 200milliseconds (ms) is obtained. In case of having videoconference betweenonly two terminals 10, the time at which the delay time is received maybe determined based on the time when the management system 50 receivesthe delay information transmitted from the request terminal 10 ratherthan based on the time when the management system 50 receives the delayinformation transmitted from the counterpart terminal 10. In case ofhaving videoconference with more than two terminals 10, the delayinformation transmitted from the counterpart terminal 10 that receivesthe image data and sound data is used to manage the date and time atwhich the delay information is received.

(Conversion Management Table)

The memory 5000 further includes a conversion management database (DB)5006, which stores a conversion management table of FIG. 16. Theconversion management table of FIG. 16 stores, for each one of aplurality of terminal IDs each assigned to the non-dedicated terminal 10(such as the non-dedicated terminal having the non-dedicated 1 or 2communications protocol), the IP address of the conversion system 80,and the IP address of the non-dedicated terminal 10.

(Quality Management Table)

The memory 5000 further includes a quality management database (DB)5007, which stores a quality management table of FIG. 17. The qualitymanagement table of FIG. 17 stores the delay time ms of image data inassociation with the quality of image data. More specifically, thequality management table of FIG. 17 indicates that the quality of imagedata to be processed by the relay device 30 is lowered, as the delaytime ms of the image data at the request terminal 10 or the counterpartterminal 10 increases. For example, when the delay time ms is equal toor greater than 0 milliseconds (ms), but less than 100 ms, the imagedata quality is high. When the delay time ms is equal to or greater than100 ms but less than 300 ms, the image data quality is medium. When thedelay time ms is equal to or greater than 300 but less than 500 ms, theimage data quality is low. When the delay time ms is equal to or greaterthan 500 ms, the management system 50 interrupts operation oftransmitting data.

(Functional Structure of Management System)

Referring back to FIG. 9, the data transmitter/receiver 51, which may beimplemented by the network I/F 209 (FIG. 8) according to an instructionreceived from the CPU 201, transmits or receives various data orinformation to or from another terminal, device, or system through thecommunications network 2.

Under control of the CPU 201 (FIG. 8), the terminal authenticator 52obtains a terminal ID and a password from the login request informationthat is received from the data transmitter/receiver 51. Using theterminal ID and the password as a search key, the terminal authenticator52 searches the terminal information management DB 5002 (FIG. 12) todetermine whether the obtained set of terminal ID and password isregistered. Based on the search result, the terminal authenticator 52determines whether the user at the terminal 10 or the terminal 10 isallowed for access.

The state manager 53, which operates according to an instructionreceived from the CPU 201 (FIG. 8), manages the operation state of therequest terminal 10 that sends the login request information using theterminal state management DB 5003 (FIG. 13). More specifically, thestate manager 53 stores the terminal ID of the request terminal 10, theoperation state of the request terminal 10, the date and time at whichthe management system 50 receives the login request information from therequest terminal 10, and the IP address of the request terminal 10. Whenthe power switch 109 is changed from the “ON” state to the “OFF” stateby the user, the state manager 53 receives the operation stateinformation indicating that the power is turned off from the terminal10, and changes the operation state of the terminal 10 from the “online”state to the “offline” state in the terminal state management table ofFIG. 13.

The determiner 55, which operates according to an instruction receivedfrom the CPU 201 (FIG. 8), determines whether the communicationsprotocol being used by the counterpart terminal 10 is the predeterminedcommunications protocol being used by the dedicated terminal 10A.

The session manager 56, which operates according to an instructionreceived from the CPU 201 (FIG. 8), stores the relay device ID of therelay device 30 for relaying contents data, the terminal ID of therequest terminal 10, the terminal ID of the counterpart terminal 10, thedelay time “ms” indicating delay in time at which the image data isreceived at the counterpart terminal 10, and the received date and timeat which the delay time information transmitted from the counterpartterminal is received at the management system 50, in a correspondingmanner, in the session management DB 5005 (FIG. 15) of the memory 5000.The session manager 56 further generates a session ID for identifying asession to be used for establishing the communication session.

The quality determiner 57, which operates according to an instructionreceived from the CPU 201 (FIG. 8), searches the quality management DB5007 (FIG. 17) using the delay time ms obtained for the selected relaydevice 30 to obtain the image data quality that is desirable forcommunication using the relay device 30. More specifically, the qualitydeterminer 57 determines the image quality of the image data to berelayed by the relay device 30, based on the image quality informationof the image data that is extracted by the memory control 59.

The delay time manager 58, which operates according to an instructionreceived from the CPU 201 (FIG. 8), manages the session management tableof FIG. 15 stored in the session management DB 5005 so as to keepupdated the value stored in the “delay time” field for the terminal IDof the counterpart terminal 10 that is extracted by the memory control59.

The memory control 59, which operates according to an instructionreceived from the CPU 201 (FIG. 8) in cooperation with the HDD 205 (FIG.8), stores various data in the memory 5000 or read out various data fromthe memory 5000. For example, the memory control 59 searches themanagement DB in the memory 5000 using a search key to read out dataassociated with the search key as a search result.

<Functional Structure of Conversion System>

The conversion system 80 includes a data transmitter/receiver 81, acommunications protocol converter 82, and a memory control 89. Theseunits shown in FIG. 9 correspond to a plurality of functions orfunctional modules, which are executed according to an instruction ofthe CPU 201 (FIG. 8) that is generated according to the conversioncontrol program being loaded from the HD 204 onto the RAM 203. Theconversion system 80 further includes a memory 8000, which may beimplemented by the HD 204 (FIG. 8) or the RAM 203. The memory 8000stores conversion rule data, which is used for converting contents data.

(Functional Structure of Conversion System)

Referring now to FIGS. 8 and 9, a functional structure of the conversionsystem 80 is explained according to an example embodiment of the presentinvention.

The data transmitter/receiver 81 of the conversion system 80 of FIG. 9,which may be implemented by an instruction from the CPU 101 (FIG. 8) incooperation with the network I/F 111 (FIG. 8), transmits or receivesvarious data or information to or from another terminal, apparatus, orsystem, through the communications network 2. The datatransmitter/receiver 81 transmits session start request information,which instructs to start a communication session (the thirdcommunication session), to the counterpart terminal having the IPaddress that is received from the relay device 30. In alternative tousing the IP address, any other information indicating the location ofthe counterpart terminal may be used such as the Uniform ResourceIdentifier (URI) of the counterpart terminal.

The communications protocol converter 82 converts the contents datatransmitted from the request terminal 10 or the contents datatransmitted from the counterpart terminal 10 according to the conversionrule data stored in the memory 8000, such that the converted contentsdata has a communications protocol compatible with the counterpartterminal 10 or the request terminal 10.

The memory control 89, which operates according to an instructionreceived from the CPU 201 (FIG. 8) in cooperation with the HDD 205 (FIG.8), stores various data in the memory 8000 or read out various data fromthe memory 8000.

<Operations of Communication System>

Referring now to FIGS. 6, 9, and 18 to 25, operation of displaying acandidate list before starting communications between two dedicatedterminals 10A, performed by the communication system 1, is explainedaccording to an example embodiment of the present invention. In thefollowing examples, it is assumed that the terminal 10 aa and theterminal 10 ca are both implemented as the dedicated terminals 10A.

FIG. 18 is a data sequence diagram illustrating operation of processinga request for starting communication with a counterpart terminal, whichis generated by a request terminal, according to an example embodimentof the present invention. In FIG. 18, various management data aretransmitted or received through the management data communicationsession “sei” of FIG. 2.

At S21, the user at the request terminal 10 aa, which is the dedicatedterminal 10A, turns on the power of the request terminal 10 aa throughthe power switch 109 (FIG. 6). The operation input 12 (FIG. 9) of therequest terminal 10 aa turns on the power of the request terminal 10 aa.

At S22, as the power of the request terminal 10 aa is turned on, thelogin request 13 of the request terminal 10 aa automatically causes thedata transmitter/receiver 11 to send the login request information thatrequests the login process to the management system 50 through thecommunications network 2. The login request information includes aterminal ID that identifies the request terminal 10 aa, and a passwordassigned to the request terminal 10 aa. The terminal ID and the passwordmay be obtained by the memory control 19 from the memory 1000, and sentto the data transmitter/receiver 11. At the time of sending the loginrequest information from the request terminal 10 aa to the managementsystem 50, the request terminal 10 aa sends an IP address of the requestterminal 10 aa such that the management system 50 can obtain the IPaddress of the request terminal 10 aa.

At S23, the terminal authenticator 52 of the management system 50searches the terminal information management table (FIG. 12) stored inthe memory 5000 using the terminal ID and the password of the loginrequest information received through the data transmitter/receiver 51.When it is determined that the terminal ID and the password of the loginrequest information is stored in the terminal information management DB5002, the terminal authenticator 52 determines that the terminal 10 aais authenticated.

At S24, when the terminal authenticator 52 authenticates that the loginrequest information is received from the authenticated terminal 10, thestate manager 53 of the management system 50 stores the operation state,the date and time at which the login request information is received,and the IP address of the terminal 10 aa, with respect to the terminalID and the terminal name of the terminal 10 aa in the terminal statemanagement table (FIG. 13) to create a record of the terminal 10 aa.Using the terminal state management table of FIG. 13, which stores theoperations state of online, the date and time of “13:40, Nov. 10, 2011”,and the terminal IP address of “1.2.1.3” in association with theterminal ID “01aa” and the terminal name “AA Terminal”, variousinformation regarding the terminal 10 aa can be managed.

At S25, the data transmitter/receiver 51 of the management system 50sends the authentication result obtained by the terminal authenticator52 to the request terminal 10 aa that has sent the login requestinformation through the communications network 2. As described above, inthis example, it is assumed that the terminal authenticator 52determines that the terminal 10 aa is an authenticated terminal.

At S26, the memory control 59 of the management system 50 searches thecandidate list management table (FIG. 14) using the terminal ID “01aa”of the request terminal 10 aa that has sent the login requestinformation as a search key to extract a terminal ID of a candidatecounterpart terminal 10 that is previously registered for the requestterminal 10 aa. In this example, the terminal IDs “01ab”, “01ba”, etc.of the terminals 10 ab, 10 ba, etc., which are associated with theterminal ID “01aa” of the request terminal 10 aa are extracted.

At S27, the memory control 59 further searches the terminal statemanagement table (FIG. 13) using the extracted terminal ID of thecandidate counterpart terminal to obtain a terminal name of thecandidate counterpart terminal 10. In this example, the operation states“offline”, “online (interrupted)”, etc. of the candidate terminals 10ab, 10 ba, etc., are extracted.

At S28, the data transmitter/receiver 51 transmits candidate listinformation to the request terminal 10 aa. The candidate listinformation includes the terminal ID and the terminal name of thecandidate counterpart terminal 10 that are extracted at S27 and S28. Thedata transmitter/receiver 11 of the terminal 10 aa receives thecandidate list information. With this candidate list information, therequest terminal 10 aa is able to know the current operation state ofeach one of the candidate counterpart terminals 10 capable ofcommunicating with the request terminal 10 aa.

At S29, the memory control 59 of the management system 50 searches thecandidate list management table (FIG. 14) using the terminal ID “01aa”of the request terminal 10 aa that has send the login requestinformation as a search key to extract the terminal ID of the otherrequest terminal that has registered the request terminal 10 aa as acandidate counterpart terminal. In this example referring to thecandidate list management table of FIG. 14, the terminal IDs “01ba”“01ca” and “01da” are extracted as the request terminals 10.

At S30, the memory control 59 searches the terminal state managementtable (FIG. 13) using the terminal ID of the request terminal 10 aa as asearch key to obtain the operation state of the request terminal 10 aathat has sent the login request information.

At S31-1 and 31-2, the data transmitter/receiver 51 sends the terminalstate information including the terminal ID “01aa” and the operationstate “online” of the request terminal 10 aa, which is obtained at S30,to the terminal having the terminal ID that is extracted at S29 and theoperation state “online”. More specifically, in this example, of theterminals 10 ba, 10 ca, and 10 da each having the terminal ID extractedat S29, the terminals 10 ba and 10 ca having the online state areselected as the terminal to which the terminal state information istransmitted. As illustrated in FIG. 18, at S31-1, the datatransmitter/receiver 51 of the management system 50 sends the terminalstate information to the terminal 10 ba. At S31-2, the datatransmitter/receiver 51 of the management system 50 sends the terminalstate information to the terminal 10 ca.

When sending the terminal state information, the memory control 59refers to the terminal state management information (FIG. 13) using theterminal IDs “01ba” and “01ca” to obtain the IP addresses of theterminals 10 ba and 10 ca. With the IP addresses, the management system50 is able to send the terminal state information including the terminalID “01aa” and the operation state “online”, to the other terminals 10 baand 10 ca each capable of communicating with the request terminal 10 aa.

Further, in this example, the terminal state management table (FIG. 13)does not manage the operation state of the terminal 10 da that is thenon-dedicated terminal 10D, such that the management system 50 does notsend the terminal state information including the terminal ID “01aa” andthe operation state “online” of the request terminal 10 aa. That is, thenon-dedicated terminal 10D is not able to obtain the operation stateinformation of the dedicated terminal 10A.

The operation of FIG. 18 is performed at the other terminal 10, as thepower is turned on through selecting the power switch 109. When theoperation input 12 receives the instruction to turn on the power, S22 toS31-1, 2 are performed.

Referring now to FIGS. 6, 9, and 19 to 22, operation of startingcommunications between two dedicated terminals 10A, performed by thecommunication system 1, is explained according to an example embodimentof the present invention. FIG. 19 is a data sequence diagramillustrating operation of processing a request for startingcommunications with the counterpart terminal 10, performed by themanagement system 50 in cooperation with the request terminal 10,according to an example embodiment of the present invention.

Referring to FIG. 19, at S41, the user at the request terminal 10 aathat is the dedicated terminal 10A, operates the operation key 108 (FIG.6) to select the terminal 10 ca as a counterpart terminal. Uponselection, the operation input 12 (FIG. 9) of the request terminal 10 aareceives a user instruction for starting communications with thecounterpart terminal 10 ca.

At S42, the data transmitter/receiver 11 of the request terminal 10 aasends the communication start request information that requests themanagement system 50 to start communication with the counterpartterminal 10 ca to the management system 50. The communication startrequest information at least includes the terminal ID “01aa” of therequest terminal 10 aa and the terminal ID “01 ca” of the counterpartterminal 10 ca.

At S43, the state manager 53 (FIG. 9) of the management system 50 looksfor records in the terminal state management DB 5003 (FIG. 13) based onthe terminal ID “01aa” of the request terminal 10 aa and the terminal ID“01ca” of the counterpart terminal 10 ca, which are included in thecommunication start request information. The state manager 53 changeseach of the operation states of the request terminal 10 aa and thecounterpart terminal 10 ca in the records, from the “online,communication OK” state to the “online, communicating” state. At thistime, the request terminal 10 aa and the counterpart terminal 10 ca havenot started communication, but the request terminal 10 aa and thecounterpart terminal 10 ca each have the communicating state. In caseanother terminal 10 tries to communicate with the request terminal 10 aaor the counterpart terminal 10 ca, the management system 50 causes theanother terminal 10 to output voice or display indicating that therequest terminal 10 aa or the counterpart terminal 10 ca is in thecommunicating state.

At S44, the session manager 56 of the management system 50 generates asession ID for a session that is to be established between the requestterminal 10 aa and the counterpart terminal 10 ca.

At S45, the management system 50 determines a communications protocol tobe used by the counterpart terminal 10 ca, for example, as describedbelow referring to FIG. 20.

Referring to FIG. 20, at S45-1, the memory control 59 searches theterminal information management table (FIG. 12) using the terminal ID“01ca” of the counterpart terminal 10 ca, which is received at the datatransmitter/receiver 51, to extract communications protocol informationof the counterpart terminal 10 ca.

At S45-2, the determiner 55 determines whether the communicationsprotocol specified by the extracted communications protocol informationis the same as the communications protocol used by the request terminal10 aa. More specifically, the determiner 55 determines whether thecommunications protocol of the counterpart terminal 10 ca is thecommunications protocol used by the request terminal 10 aa that is thededicated terminal 10A. The determiner 55 determines that thecommunications protocol is the same when both of the call controlprotocol and the encoding format are the same. When at least one of thecall control protocol and the encoding format is different, thedeterminer 55 determines that the communications protocol is differentbetween the counterpart terminal 10 ca and the request terminal 10 aa.

When it is determined that the communications protocol is the same(“YES” at S45-2), the operation proceeds to S61 of FIG. 21. When it isdetermined that the communications protocol is different (“NO” atS45-2), the operation proceeds to S45-3.

In this example, the counterpart terminal 10 ca is the dedicatedterminal 10A, which communicates using the communications protocol thatis the same as the communications protocol of the request terminal 10aa. In such case, the operation proceeds to FIG. 21 to establish acommunication session between the dedicated communication terminals 10A.Further, in this example illustrated in FIG. 21, the relay device 30 a,which is connected to the request terminal 10 aa through the LAN 2 a, isselected as a relay device to relay contents data between the requestterminal 10 aa and the counterpart terminal 10 ca.

Referring to FIG. 21, at S61, the data transmitter/receiver 51 of themanagement system 50 transmits session initiate request information,which requests to initiate a communication session being established bythe relay device 30 a, to the relay device 30 a. The session initiaterequest information includes the session ID generated at S44, the IPaddress of the request terminal 10 aa, and the IP address of thecounterpart terminal 10 ca. The IP addresses of the terminals 10 aremanaged by the management system 50 using the terminal state managementtable of FIG. 13. The management system 50 further transmits the IPaddress of the management system 50 to the relay device 30 a togetherwith the session initiate request information. The datatransmitter/receiver 31 of the relay device 30 a receives the sessioninitiate request information and the IP address of the management system50.

At S62, the data transmitter/receiver 31 of the relay device 30 ainitiates a contents data communication session.

At S63, the data transmitter/receiver 31 of the relay device 30 atransmits session start request information, which requests to start acommunication session, to the request terminal 10 aa. The session startrequest information includes the session ID received from the managementsystem 50. The relay device 30 a further sends the IP address of therelay device 30 a to the request terminal 10 aa, with the session startrequest information. The data transmitter/receiver 11 of the requestterminal 10 aa receives the session start request information and the IPaddress of the relay device 30 a.

At S64, the data transmitter/receiver 31 transmits session start requestinformation, which requests to start a communication session, to thecounterpart terminal 10 ca. The session start request informationincludes the session ID received from the management system 50. Therelay device 30 a further sends the IP address of the relay device 30 ato the counterpart terminal 10 ca, with the session start requestinformation. The data transmitter/receiver 11 of the counterpartterminal 10 ca receives the session start request information and the IPaddress of the relay device 30 a.

At S65-1, the request terminal 10 aa and the relay device 30 a establisha contents data communication session, that is, the first communicationsession “sed1” of FIG. 2, to transmit or receive contents data.

At S65-2, the counterpart terminal 10 ca and the relay device 30 aestablish a contents data communication session, that is, the secondcommunication session “sed2” of FIG. 2, to transmit or receive contentsdata.

Referring now to FIG. 22, operation of transmitting and receivingcontents data such as image data and sound data between the requestterminal and the counterpart terminal to carry out videoconference,performed by the communication system 1, is explained according to anexample embodiment of the present invention. FIG. 22 is a data sequencediagram illustrating operation of transmitting or receiving contentsdata between the dedicated terminals 10A. In this example, the contentsdata such as the image data and the sound data flows in a direction fromthe request terminal 10 aa to the counterpart terminal 10 ca, or inanother direction from the counterpart terminal 10 ca to the requestterminal 10 aa. Since operation such as transmission and reception ofthe contents data or detection of delay time is the same for both of thedirections, the following example focuses on communication in which dataflows from the request terminal 10 aa to the counterpart terminal 10 ca.

Referring to FIG. 22, at S81, the data transmitter/receiver 11 of therequest terminal 10 aa sends the contents data to the relay device 30 athrough the communications network 2 in the contents data communicationssession “sed1”. The contents data includes image data such as image dataof an object captured by the imaging unit 14 and sound data that isinput through the sound input 15 a. In this example, it is assumed thatthe high-quality image data based on the low-level resolution imagedata, the medium-level resolution image data, and the high-levelresolution image data, and the sound data, are transmitted. Accordingly,the data transmitter/receiver 31 of the relay device 30 a receives theimage data of three different resolution levels, and the sound data.

At S82, the data quality checker 33 searches the data quality managementDB 3001 (FIG. 10) using the IP address “1.3.1.3” of the counterpartterminal 10 ca as a key to obtain the image quality information, and todetermine whether to change quality of image data to be transmitted tothe relay device 30 a or interrupt transmission of image data.

In this example, the quality of image data to be transmitted to therelay device 30 a is the high-quality image data. Since the image datathat is received at the data transmitter/receiver 31 has the qualitythat is the same as the quality of the image data obtained from the dataquality management DB 3001, at S83, the relay device 30 a sends thehigh-quality image data and the sound data to the counterpart terminal10 ca in the contents data communication session “sed2”, withoutapplying further image processing.

The counterpart terminal 10 ca receives the high quality image data thatis generated based on the low-level resolution image data, medium-levelresolution image data, and high-level resolution image data, and thesound data, at the data transmitter/receiver 11. The display control 16combines the image data of three different resolution levels into thehigh quality image data for display onto the display 120 ca. Further,the sound output 15 b outputs the sound based on the sound data.

At S84, the delay detector 17 of the counterpart terminal 10 caperiodically detects a delay time indicating the time at which the imagedata is received at the data transmitter/receiver 11, for example, everyone second. In this example, it is assumed that the delay time of 200 msis obtained.

At S85, the data transmitter/receiver 11 of the counterpart terminal 10ca sends the delay information indicating the delay time of 200 ms tothe management system 50 through the communications network 2, duringthe management data communication session “sei”. With the delayinformation, the management system 50 is notified of the delay time, andthe IP address “1.3.1.3” of the counterpart terminal 10 ca that has sentthe delay information.

At S86, the delay time manager 58 of the management system 50 searchesthe terminal state management DB 5003 (FIG. 13) using the IP address“1.3.1.3” of the counterpart terminal 10 ca as a search key to extractthe terminal ID “01ca” of the counterpart terminal 10 ca. The delay timemanager 58 stores the delay time of 200 ms obtained from the delayinformation in a “delay time” field of the record of the terminal ID“01ca” of the session management table stored in the session managementDB 5005 (FIG. 15).

At S87, the quality determiner 57 searches the quality management DB5007 (FIG. 17) using the delay time of 200 ms to extract the imagequality information, that is, the image data quality of “MEDIUM”. Basedon the extracted image data quality, the quality determiner 58determines that the quality of image data suitable for the delay time of200 ms is medium.

At S88, the data transmitter/receiver 51 searches the relay devicemanagement DB 5001 (FIG. 11) using the relay terminal ID “111a”, whichis stored in the session management DB (FIG. 15) in association with thecounterpart terminal ID “01ca”, to extract the IP address “1.2.1.2” ofthe relay device 30 a.

At S89, the data transmitter/receiver 51 sends the image qualityinformation indicating the medium-level image data quality that has beendetermined at S87, to the relay device 30 a through the communicationsnetwork 2 during the management data communication session “sei”. Theimage quality information is transmitted with the IP address “1.3.1.3”of the counterpart terminal 10 ca, which was used as a search key atS86.

At S90, the data quality manager 34 of the relay device 30 a stores theIP address “1.3.1.3” of the counterpart terminal 10 ca in associationwith the “medium-level” quality image data to be relayed by thecounterpart terminal 10 ca, in the data quality management DB 3001 (FIG.10).

At S91, the request terminal 10 aa transmits the high quality image dataincluding the low-level resolution image data, the medium-levelresolution image data, and the high-level resolution image data, and thesound data, to the relay device 30 a during the contents datacommunication session “sed1”, in a substantially similar manner asdescribed above referring to S81.

At S92, the data quality checker 33 of the relay device 30 a searchesthe data quality management DB 3001 (FIG. 10) using the IP address“1.3.1.3” of the counterpart terminal 10 ca as a search key to determinewhether to extract the quality of the image data suitable for thecounterpart terminal 10 ca or to interrupt transmission of image data,in a substantially similar manner as described above referring to S82.

At S93, since the image data quality that is stored for the counterpartterminal 10 ca is the medium-level, which is lower than the quality ofthe image data that is received at the data transmitter/receiver 31, thedata quality changer 35 changes the quality of the image data from thehigh-level to the medium level. In this example, the quality of thesound data remains the same.

At S94, the data transmitter/receiver 31 of the relay device 30 a sendsthe image data having the quality that is lowered to the medium-level,and the sound data, to the counterpart terminal 10 ca through thecommunications network 2, during the contents data communication session“sed2”. The data transmitter/receiver 11 of the counterpart terminal 10ca receives the medium-quality image data that is generated based on thelow-level resolution image data and the medium-level resolution imagedata, and the sound data. The display control 16 of the counterpartterminal 10 ca combines the image data of two different resolutionlevels to generate the medium-level image data for display on thedisplay 120 ca. Further, the sound output 15 b outputs sounds generatedbased on the sound data.

As described above, when any delay in receiving the image data at thecounterpart terminal 10 ca is observed, the relay device 30 a changesthe quality of image data by lowering the quality of image data.Accordingly, the users participating the videoconference are able tocarry out communication more smoothly. The management system 50 is ableto provide the above-described services in controlling quality of imagedata, when the terminals 10 are dedicated terminals 10A.

Referring now to FIGS. 20, and 23 to 25, operation of transmitting orreceiving contents data according to the second communications pattern,in which the dedicated terminal 10A and the non-dedicated terminal 10Dcommunicate with each other, is explained according to an exampleembodiment of the present invention. In this example, it is assumed thatthe terminal 10 aa that is the dedicated terminal 10A communicates withthe terminal 10 da that is the non-dedicated terminal 10D. Morespecifically, the communications protocol used by the dedicated terminal10 aa has a call control protocol that is the (4) IM protocol or the (7)extended IM based protocol, and the encoding format that is SVC. For thecommunications protocol used by the non-dedicated terminal 10 da, thecall control protocol is (1) session initial protocol (SIP) and theencoding format is AVC.

Before starting communications with the counterpart terminal 10 da, therequest terminal 10 aa sends the login request information to themanagement system 50 in a substantially similar manner as describedabove referring to FIG. 18. In this example, however, the counterpartterminal 10 ca is selected as one of the candidate counterpart terminals10. For example, the counterpart terminal 10 ca may be replaced by thecounterpart terminal 10 da, or the counterpart terminal 10 da may beadditionally included as one of candidate counterpart terminals 10 thatmay be selected by the request terminal 10 aa.

Assuming that the user at the request terminal 10 aa selects thecounterpart terminal 10 da to start communications at S41 of FIG. 19,the request terminal 10 aa transmits the communication start requestinformation including the terminal ID of the counterpart terminal 10 dato the management system 50. The management system 50 prepares for acommunication session in a substantially similar manner as describedabove referring to FIG. 19, except that the terminal ID of thecounterpart terminal 10 da is used as a search key. At S45-2 of FIG. 20,the determiner 55 of the management system 50 determines that thecommunications protocol of the counterpart terminal 10 da is differentfrom the communications protocol of the request terminal 10 aa (“NO” atS45-2). In such case, the operation proceeds to S45-3.

At S45-3, the memory control 59 searches the conversion management table(FIG. 16) stored in the conversion management DB 5006 using the terminalID “01da” of the counterpart terminal 10 da, which is received at thedata transmitter/receiver 51, to extract the IP address “1.3.2.2” of theconversion system 80 and the IP address “1.3.2.3” of the counterpartterminal 10 da. The operation further proceeds to S101 of FIG. 23.

FIG. 23 is a data sequence diagram illustrating operation ofestablishing a contents data communication session between the dedicatedterminal 10A and the non-dedicated terminal 10D, according to an exampleembodiment of the present invention. Further, in this exampleillustrated in FIG. 23, the relay device 30 a, which is connected to therequest terminal 10 aa through the LAN 2 a, is selected as a relaydevice to relay contents data between the request terminal 10 aa and thecounterpart terminal 10 da.

At S101, the data transmitter/receiver 51 of the management system 50transmits session initiate request information, which requests toinitiate a contents data communication session, to the relay device 30 athrough the communications network 2. The session initiate requestinformation includes a session ID that is generated at S44, the IPaddress of the request terminal 10 aa, the IP address of the conversionsystem 80, and the IP address of the counterpart terminal 10 da. The IPaddress of the request terminal 10 aa may be obtained from the terminalstate management table (FIG. 13). The IP address of the conversionsystem 80 and the IP address of the counterpart terminal 10 da areextracted at S45-3.

The management system 50 further sends the IP address of the managementsystem 50 to the relay device 30 a, with the session initiate requestinformation. The data transmitter/receiver 31 of the relay device 30 areceives the session initiate request information and the IP address ofthe management system 50.

At S102, the data transmitter/receiver 31 of the relay device 30 ainitiates a contents data communication session.

At S103, the data transmitter/receiver 31 of the relay device 30 atransmits session start request information, which requests to start acontents data communication session, to the request terminal 10 aa. Thesession start request information includes the session ID received fromthe management system 50. The relay device 30 a further sends the IPaddress of the relay device 30 a to the request terminal 10 aa, with thesession start request information. The data transmitter/receiver 11 ofthe request terminal 10 aa receives the session start requestinformation and the IP address of the relay device 30 a.

At S104, the data transmitter/receiver 31 of the relay device 30 atransmits session start request information, which requests to start acontents data communication session, to the conversion system 80. Thesession start request information includes the session ID and the IPaddress of the counterpart terminal 10 da, which are received from themanagement system 50. The relay device 30 a further sends the IP addressof the relay device 30 a to the conversion system 80, with the sessionstart request information. The data transmitter/receiver 81 of theconversion system 80 receives the session start request information andthe IP address of the relay device 30 a.

At S105, the data transmitter/receiver 81 of the conversion system 80transmits session start request information, which requests to start acontents data communication session, to the counterpart terminal 10 da.The session start request information includes the session ID receivedfrom the management system 50. The conversion system 80 furthertransmits the IP address of the conversion system 80, with the sessionstart request information, to the counterpart terminal 10 da. The datatransmitter/receiver 11 of the counterpart terminal 10 da receives thesession start request information and the IP address of the conversionsystem 80.

At S106-1, the request terminal 10 aa and the relay device 30 aestablish a contents data communication session, that is, the firstcommunication session “sed11” of FIG. 4, to transmit or receive contentsdata.

At S106-2, the relay device 30 a and the conversion system 80 establisha contents data communication session, that is, the second communicationsession “sed12” of FIG. 4, to transmit or receive contents data.

At S106-3, the conversion system 80 and the counterpart terminal 10 daestablish a contents data communication session, that is, the thirdcommunication session “sed13” of FIG. 4, to transmit or receive contentsdata.

Referring now to FIG. 24, operation of transmitting and receivingcontents data such as image data and sound data between the requestterminal and the counterpart terminal to carry out videoconference,performed by the communication system 1, is explained according to anexample embodiment of the present invention. In this example illustratedin FIG. 24 contents data is transmitted or received between thededicated terminal 10A and the non-dedicated terminal 10D.

At S121, the data transmitter/receiver 11 of the request terminal 10 aasends the contents data to the relay device 30 a through thecommunications network 2 in the first communication session “sed11”. Thecontents data includes image data such as image data of an objectcaptured by the imaging unit 14 and sound data that is input through thesound input 15 a. In this example, it is assumed that the high-qualityimage data based on the low-level resolution image data, themedium-level resolution image data, and the high-level resolution imagedata, and the sound data, are transmitted. Accordingly, the datatransmitter/receiver 31 of the relay device 30 a receives the image dataof three different resolution levels, and the sound data.

At S122, the data transmitter/receiver 31 of the relay device 30 atransmits the contents data, which includes the image data of threedifferent resolution levels and the sound data, to the conversion system80 through the communications network 2, in the second communicationsession “sed12”. Accordingly, the data transmitter/receiver 81 of theconversion system 80 receives the image data of three differentresolution levels, and the sound data.

At S123, the communications protocol converter 82 of the conversionsystem 80 refers to conversion rule data stored in the memory 8000, andconverts the image data of three different resolution levels from acommunications protocol of the request terminal 10 aa to acommunications protocol of the counterpart terminal 10 da. In thisexample, the image data of three different resolution levels that areillustrated in FIGS. 3A to 3C is converted to the image data of oneresolution level that is illustrated in FIG. 5. As described abovereferring to FIG. 5, the image data of FIG. 5 has medium-levelresolution.

At S124, the data transmitter/receiver 81 of the conversion system 80transmits the medium-level resolution image data and the sound data tothe counterpart terminal 10 da, through the communications network 2, inthe third communication session “sed13”. The data transmitter/receiver11 of the counterpart terminal 10 da receives the medium-levelresolution image data and the sound data.

At S125, the data transmitter/receiver 11 of the counterpart terminal 10da transmits the contents data, which includes the medium-levelresolution image data and the sound data, to the conversion system 80through the communications network 2 in the third communication session“sed13”. The data transmitter/receiver 81 of the conversion system 80receives the medium-level resolution image data and the sound data.

At S126, the communications protocol converter 82 of the conversionsystem 80 refers to the conversion rule data stored in the memory 800,and converts the medium-level resolution image data and the sound datafrom the communications protocol of the counterpart terminal 10 da tothe communications protocol of the request terminal 10 aa. Morespecifically, at S126, the communications protocol converter 82 convertsthe medium-level resolution image data of FIG. 5, to the low-levelresolution image data of FIG. 25A, the low-medium-level resolution imagedata of FIG. 25B, and the medium-level resolution image data of FIG.25C.

Referring to FIG. 25A, the low-level resolution image data has 160pixels in the horizontal direction and 120 pixels in the verticaldirection. Referring to FIG. 25C, the medium-level resolution image datahas 320 pixels in the horizontal direction and 240 pixels in thevertical direction. Referring to FIG. 25B, the low-medium-levelresolution image data has 240 pixels in the horizontal direction and 180pixels in the vertical direction, such that the low-medium resolutionimage data has a resolution level greater than the resolution of thelow-level resolution image data, but lower than the resolution of themedium-level resolution image data.

As the medium-level resolution image data is received from thenon-dedicated terminal 10D, the conversion system 80 is not able togenerate the high-level resolution image data of FIG. 3C, which ishigher in resolution than the medium-level resolution image data. Forthis reasons, the medium-level resolution image data transmitted fromthe counterpart terminal 10 da is treated as the high-level resolutionimage data. Based on the high-level resolution image data, image data ofthree different resolution levels are generated as described abovereferring to FIGS. 25A to 25C.

At S127, the data transmitter/receiver 81 of the conversion system 80transmits the image data of three different resolution levels and thesound data to the relay device 30 a, through the communications network2, in the second communication session “sed12”. The datatransmitter/receiver 31 of the relay device 30 a receives the image dataof three different resolution levels and the sound data.

At S128, the data transmitter/receiver 31 of the relay device 30 atransmits the image data of three different resolution levels and thesound data to the request terminal 10 aa, through the communicationsnetwork 2, in the first communication session “sed11”. The datatransmitter/receiver 11 of the request terminal 10 aa receives the imagedata of three different resolution levels and the sound data.

Referring now to FIGS. 26 and 27, a third communication pattern in whichthe non-dedicated terminal 10D participates in the communication sessionestablished between the dedicated terminals 10A as illustrated in FIG.21, is explained according to an example embodiment of the presentinvention. FIG. 26 is a data sequence diagram illustrating operation ofprocessing a participation request that requests to participate in thecommunication session, generated by the non-dedicated terminal 10D,performed by the communication system 1, according to an exampleembodiment of the present invention. In this example, the terminal 10 dbis the non-dedicated terminal that requests for participation, which maybe referred to as the participation request terminal 10 db. Further, itis assumed that the user at the request terminal 10 aa notifies the userat the participation request terminal 10 db of the session ID of thecommunication session currently established as described above referringto FIG. 21, for example, by telephone or email. The session ID of thecommunication session may be obtained at S63 (FIG. 21). In case theterminal 10 aa and the terminal 10 da are communicating as illustratedin FIG. 23, the session ID of the communication session may be obtainedat S106 (FIG. 23).

As illustrated in FIG. 26, at S141, the data transmitter/receiver 11 ofthe participation request terminal 10 db sends session start requestinformation, which requests to start a communication session, to theconversion system 80. The session start request information includes thesession ID (“se01”), which is notified from the user at the requestterminal 10 aa. With the session start request information, the IPaddress of the participation request terminal 10 db, that is, thenon-dedicated terminal 10D is transmitted. More specifically, the userat the participation request terminal 10 db enters the session ID “se01”through the operation key 108 of the participation request terminal 10db. The data transmitter/receiver 80 of the conversion system 80receives the session start request information and the IP address of theparticipation request terminal 10 db.

At S142, the data transmitter/receiver 81 of the conversion system 80transmits session start determination request information (“sessionstart request information” in FIG. 26) to the management system 50through the communications network 2, in the communication session“sei2”. The session start determination request information includes thesession ID and the IP address of the participation request terminal 10db, which are received at S141. With the session start determinationrequest information, the IP address of the conversion system 80 istransmitted. The data transmitter/receiver 51 of the management system50 receives the session start determination request information and theIP address of the conversion system 80.

At S143, the determiner 55 of the management system 50 determineswhether to allow the participation request terminal 10 db to start acommunication session, that is, to participate in the communicationsession indicated by the session ID.

Referring now to FIG. 27, operation of determining whether to allowstarting of a communication session, performed by the determiner 55 ofthe management system 50, is explained according to an exampleembodiment of the present invention.

At S143-1, the memory control 59 of the management system 50 searchesthe session management table (FIG. 15) using the session ID “se01” thatis received at S142 as a search key to specify a record associated withthe session ID “se01”. More specifically, the memory control 59 readsthe terminal ID field associated with the session ID “se01”.

At S143-2, the determiner 55 determines whether the extracted record forthe session ID “se01” includes information regarding the terminal IDs ofthe request terminal 10 and the counterpart terminal 10. When it isdetermined that the record for the session ID “se01” includes theterminal IDs (“YES” at S143-2), the operation proceeds to S143-3. AtS143-3, the memory control 59 reads out the terminal IDs “01aa” and“01ca” of the terminals 10 associated with the session ID “se01”, andfurther searches the “request terminal ID” field in the candidate listmanagement table (FIG. 14) using the obtained terminal IDs as a searchkey to obtain the candidate counterpart terminal IDs, respectively, forthe terminal ID “01aa” and the terminal ID “01ca”.

At S143-4, the memory control 19 searches the terminal informationmanagement table (FIG. 12) using the terminal IDs of the candidatecounterpart terminals obtained at S143-3 as a search key to obtain theIP addresses of the candidate counterpart terminals.

At S143-5, the determiner 55 determines whether the IP address of theparticipation request terminal 10 that is the non-dedicated terminal10D, which is received at S142, is included in the obtained IP addressesof the candidate counterpart terminals.

When the determiner 55 determines that the IP address of thenon-dedicated terminal 10D is included (“YES” at S143-5), the operationproceeds to S143-6 to generate a determination result indicating thatthe communication session is started.

When the determiner 55 determines that the record for the session ID“se01” does not include the session ID at S143-2 (“NO” at S143-2), orwhen the determiner 55 determines that the IP address of thenon-dedicated terminal 10D is not included in the obtained IP addressesof the candidate counterpart terminals (“NO” at S143-5), the operationproceeds to S143-7 to generate a determination result indicating thatthe communication session is not started.

Referring back to FIG. 26, at S144, the data transmitter/receiver 51 ofthe management system 50 sends the determination result obtained at S143to the conversion system 80.

Assuming the determination result indicates to start the communicationsession, at 145-1, the relay device 30 a and the conversion system 80establish a third contents data communication session “sed3” to transmitor receive contents data. At S145-2, the conversion system 80 and theparticipation request terminal 10 db that is the non-dedicated terminal10D establish a fourth contents data communication session “sed4” totransmit or receive contents data.

As described above, in at least one of the above-described exampleembodiments, when the participation request terminal 10 that is thenon-dedicated terminal 10D requests to participate in a communicationsession that has been carried out by a plurality of communicationterminals 10, the management system 50 is able to determine whether toallow the participation request terminal 10 to participate in thesession, using the IP address of the participation request terminal 10.

To improve the security, the management system 50 determines whether theuser at the participation request terminal 10 that is the non-dedicatedterminal 10D is a user, who is known to any one of the users who areparticipating in the session. The user at the terminal 10 most likely toregister the terminal ID of the terminal that such user operates, as acandidate counterpart terminal in the candidate list management table ofFIG. 14. As described above, the management system 50 manages the IPaddress of the non-dedicated terminal 10D using the terminal informationmanagement table of FIG. 12. When the IP address of the participationrequest terminal 10 that is the non-dedicated terminal 10D and thesession ID are received from the participation request terminal 10, themanagement system 50 refers to the session management table of FIG. 16and the candidate list management table of FIG. 14 to obtain one or moreterminal IDs of the candidate counterpart terminals 10 that arepreviously registered for any one of the request terminal 10 and thecounterpart terminal 10 having the session indicated by the receivedsession ID. The management system 50 further refers to the terminalinformation management table of FIG. 12 to determine whether the IPaddress of the participation request terminal 10 (non-dedicatedterminal) matches any one of the terminal IP addresses of thenon-dedicated terminals 10 that are managed by the management system 50.

With this configuration, the management system 50 is able to reject theparticipation request from the participation request terminal 10, whenthe participation request terminal 10 is not registered for managementby the management system 50, thus improving the security in system.Further, determination of whether to allow the participation requestterminal 10 to participate in the session may be made using the IPaddress of the participation request terminal 10, which can be obtainedfrom the participation request terminal 10 without lowering thesecurity.

In another aspect, the session initiate request information, which istransmitted from the management system 50 to the relay device 30 a,includes the IP addresses of the request terminal 10, the conversionsystem 80, and the counterpart terminal 10. The relay device 30 a sendsthe session start request information to the request terminal 10 usingthe IP address of the request terminal 10, and further sends the sessionstart request information including the IP address of the counterpartterminal 10 to the conversion system 80 using the IP address of theconversion system 80. The conversion system 80 sends the session startrequest information to the counterpart terminal 10 using the IP addressof the counterpart terminal 10.

With transmission of the session initiate request information from themanagement system 50, three contents data sessions are established: afirst contents data session “sed11” between the relay device 30 and therequest terminal 10; a second contents data session “sed12” between therelay device 30 and the conversion system 80; and a third contents datasession “sed13” between the conversion system 80 and the counterpartterminal 10. With this configuration, even when the request terminal 10and the counterpart terminal 10 use different communications protocols,the terminals 10 are able to communicate with each other through theconversion system 80 that converts the communications protocol.

In the above-described examples, it is assumed that, when theparticipation request terminal 10 sends the participation request forparticipating in a session, a first communication terminal 10 and asecond communication terminal 10 carryout communication through thecontents data session that has been already established. In theabove-described examples, the request terminal 10 or the dedicatedterminal 10A is used as one example of the first communication terminal,and the counterpart terminal 10 or the non-dedicated terminal 10D isused as one example of the second communication terminal. Alternatively,the counterpart terminal 10 or the non-dedicated terminal 10D may beused as one example of the first communication terminal, and the requestterminal 10 or the dedicated terminal 10A may be used as one example ofthe second communication terminal.

In the above-described third communication pattern, the participationrequest terminal 10 requests to participate in the communication sessionthat has been established between the dedicated terminals 10A (the firstcommunication pattern as illustrated in FIG. 21). Alternatively, theparticipation request terminal 10 may request to participate in thecommunication session that has been established between the dedicatedterminal 10A and the non-dedicated terminal 10D (the secondcommunication pattern as illustrated in FIG. 23).

More specifically, it is assumed that the participation request terminal10 communicates using the communications protocol that is different fromthe communications protocol used by at least one of the first and secondcommunication terminals 10 that communicate through the session.

Further, a number of communication terminals 10 that has alreadyestablished the session is not limited to two, but could be more thantwo.

Further, the contents data described above is one example of data, or asignal, that may be transmitted or received through a communicationsnetwork. The data to be transmitted or received may include text data orimage file data, which may be transmitted or received together with thecontents data including image data and/or sound data. In such case, thecommunication terminal 10 may be implemented by an informationprocessing apparatus that transmits or receives data such as the text orimage file data. The management system 50 may be implemented by a filemanagement system capable of managing data such as the text or imagefile data. The communication system 1 may manage data such as the textor image file data, in addition to the contents data including imagedata and/or sound data.

In the above-described example embodiments, the management system 50manages information regarding the communications protocol using theterminal information management table (FIG. 12). Alternatively, therequest terminal 10 may manage the communications protocol informationregarding the counterpart terminals 10 including the non-dedicatedterminals 10D.

In such case, at S42 of FIG. 19, the request terminal 10 may send thecommunications protocol information of the counterpart terminal 10 tothe management system 50, in addition to the terminal ID of the requestterminal 10 and the terminal ID of the counterpart terminal 10 as thestart request information.

In one example, at S41 of FIG. 19, the display control 16 may cause thedisplay 120 to additionally display a selection screen that asks theuser whether to select the non-dedicated terminal 10D as the counterpartterminal to start communication, for example, by indicating that thecandidate counterpart terminal 10 is the non-dedicated terminal 10 whenthe non-dedicated terminal 10 is selected. In another example, thedisplay control 16 may cause the display 120 to additionally displayinformation indicating that the candidate counterpart terminal 10 is thenon-dedicated terminal, when the candidate counterpart terminal 10 islisted as a part of the candidate list.

When the non-dedicated terminal 10 is selected, at S42 of FIG. 19, therequest terminal 10 aa sends information indicating that the counterpartterminal 10 is the non-dedicated terminal 10D, such as thecommunications protocol information, to the management system 50 inaddition to the terminal IDs of the request and counterpart terminals.In such case, the management system 50 does not perform S45-1 of FIG.20. More specifically, at S45-2, the management system 50 determinesthat the counterpart terminal 10 is the non-dedicated terminal 10 basedon the communications protocol information included in the start requestinformation (“NO” at S45-3), and the operation proceeds to S45-3 of FIG.20.

In another example, in alternative to requesting the user to select thecounterpart terminal through the selection screen, the request terminal10 may receive a user input regarding the counterpart terminal 10 invarious other ways. For example, when the user knows the locationinformation of the counterpart terminal 10, the operation input 12 mayreceive a user input that inputs the location information of thecounterpart terminal 10, such as the IP address of the counterpartterminal 10. In such case, at S42 of FIG. 19, the request terminal 10sends the location information of the counterpart terminal 10 (such asthe IP address) and the communications protocol information indicatingthat the counterpart terminal 10 is the non-dedicated terminal, to themanagement system 50 as information regarding the counterpart terminalto be included in the start request information. At S45-2, thedeterminer 55 of the management system 50 determines that thecounterpart terminal 10 is not the dedicated terminal 10, and theoperation proceeds to S45-3. At S45-3, the memory control 59 obtains thelocation information of the conversion system 80, using the locationinformation of the non-dedicated terminal 10 that is received from therequest terminal 10, and the operation proceeds to S101.

In the above-described example embodiments, the relay device 30, themanagement system 50, the conversion system 80, the program providingsystem 90, and the maintenance system 100 may each be implemented by asingle computer. Alternatively, any number of parts, functions, ormodules of the relay device 30, the management system 50, the conversionsystem 80, the program providing system 90, and the maintenance system100 may be classified into a desired number of groups to be carried outby a plurality of computers. In case the program providing system 90 isimplemented by the single computer, the program to be provided by theprogram providing system 90 may be transmitted, one module by onemodule, after dividing into a plurality of modules, or may betransmitted at once. In case the program providing system 90 isimplemented as a plurality of computers, each computer may transmit eachmodule that is stored in its memory, after the program is divided into aplurality of modules.

Further, the illustrated elements of the communication management system50 and the conversion system 80 can be combined into a single serverapparatus, or divided between a plurality of machines in combinationsother than that shown for example in FIG. 1.

Further, the terminal ID of the request terminal 10 may be previouslystored in a memory of the terminal 10 before shipping, or may be storedin the memory of the terminal 10 through the user input after shipping.

In the above-described example embodiments, the communications protocolfor the dedicated terminal 10A is (4) IM protocol or the (7) extended IMbased protocol, and the communications protocol for the non-dedicatedterminal 10D is (1) session initial protocol (SIP). Alternatively, anydesired combination of communications protocol and encoding format maybe possible, as long as the communications protocol differs between thededicated and non-dedicated terminals. For example, the communicationsprotocol for the dedicated terminal 10A may be (4) IM protocol or the(7) extended IM based protocol, and the communications protocol for thenon-dedicated terminal 10D may be H.323. In another example, thecommunications protocol for the dedicated terminal 10A may be (4) IMprotocol and the communications protocol for the non-dedicated terminal10D may be the (7) extended IM based protocol.

A recording medium storing any one of the terminal control program,relay control program, conversion control program, and communicationmanagement program, or a storage device such as the HDD 204 that storesany one of the terminal control program, relay control program,conversion control program, and communication management program, or theprogram providing system 90 provided with the HD 204 storing any one ofthe terminal control program, relay control program, conversion controlprogram, and communication management program, may be distributed withinthe country or to another country as a computer program product.

In the above-described examples, the quality of image data to beprocessed by the relay device 30, which is determined based oninformation obtainable from any one of the data quality management tableof FIG. 10 and the quality management table of FIG. 17, is analyzed interms of image resolution. Alternatively, any other criteria may be usedto analyze quality of image data including, for example, depth of image,sampling frequency in case of sound data, and bit length in case ofsound data. Further, the sound data may be transmitted or received inthree items of sound data including high-resolution sound data,medium-resolution sound data, and low-resolution sound data.

Further, the date and time information stored in the relay devicemanagement table of FIG. 11 or the terminal state management table ofFIG. 13, or the delay information stored in the session management tableof FIG. 15, is expressed in terms of date and time. Alternatively, thedate and time information or the delay information may be expressed onlyin terms of time such as the time at which information is received.

Further, in the above-described examples, the relay device IP address ofthe relay device 30 and the terminal IP address of the terminal 10 arerespectively managed using the relay device management table of FIG. 11and the terminal state management table of FIG. 13. Alternatively,location information for identifying a location of the relay device 30and/or the terminal 10 on the network may each be managed in variousother ways. The other examples of location information include, but notlimited to, Fully Qualified Domain Name (FQDN). In such case, thecommunication system 1 is provided with a domain name system (DNS)server that obtains the IP address that corresponds to the FQDN of therelay device 30 or the terminal 10.

In the above-described examples, the communication system 1 of FIG. 1 istreated as a videoconference system. Alternatively, the communicationsystem 1 of FIG. 1 may be implemented as a teleconference system such asthe IP teleconference system or the Internet teleconference system.Alternatively, the communication system 1 of FIG. 1 may be implementedas a car navigation system. For example, the request terminal 10 may beimplemented as a car navigation system that is installed onto anautomobile. The counterpart terminal 10 may be implemented as amanagement terminal or server at a management center that manages thecar navigation system or a car navigation system that is installed ontoanother automobile. In another example, the communication system 1 ofFIG. 1 may be implemented as a communication system having a portablephone. In such case, the terminal 10 is implemented as the portablephone.

In the above-described examples, the contents data is assumed to includeimage data and sound data. Alternatively, the contents data may includeany other type of data that affects human senses of sight in alternativeto image data, or any other type of data that affects human senses ofhearing in alternative to sound data. Alternatively, the contents datamay include any other type of data that affects human senses of sight,smell, taste, touch, and hearing. In case the contents data that affectshuman senses of touch, the terminal 10 may convey the contents data thatreflects senses of touch that is felt by a user at the terminal 10 toanother terminal 10 through the communications network 2. In case thecontents data that affects human senses of smell, the terminal 10 mayconvey the contents data that affects senses of smell felt by a user atthe terminal 10 to another terminal 10 through the communicationsnetwork 2. In case the contents data that affects human senses of taste,the terminal 10 may convey the contents data that affects senses oftaste felt by a user at the terminal 10 to another terminal 10 throughthe communications network 2.

Further, the contents data may only include one type of contents dataselected from sight data such as image data, hearing data such as sounddata, touch data, smell data, and taste data.

Further, in the above-described examples, the communication system 1 isimplemented as a videoconference system for use at offices. Otherexamples of use of the communication system 1 include, but not limitedto, meetings, casual conversation among family members or friends, anddistribution of information in one direction.

Numerous additional modifications and variations are possible in lightof the above teachings. It is therefore to be understood that within thescope of the appended claims, the disclosure of the present inventionmay be practiced otherwise than as specifically described herein. Forexample, elements and/or features of different illustrative embodimentsmay be combined with each other and/or substituted for each other withinthe scope of this disclosure and appended claims.

Further, any of the above-described devices or units can be implementedas a hardware apparatus, such as a special-purpose circuit or device, oras a hardware/software combination, such as a processor executing asoftware program.

Further, as described above, any one of the above-described and othermethods of the present invention may be embodied in the form of acomputer program stored in any kind of storage medium. Examples ofstorage mediums include, but are not limited to, flexible disk, harddisk, optical discs, magneto-optical discs, magnetic tapes, nonvolatilememory cards, ROM (read-only-memory), etc.

Alternatively, any one of the above-described and other methods of thepresent invention may be implemented by ASIC, prepared byinterconnecting an appropriate network of conventional componentcircuits or by a combination thereof with one or more conventionalgeneral purpose microprocessors and/or signal processors programmedaccordingly.

The present invention can be implemented in any convenient form, forexample using dedicated hardware, or a mixture of dedicated hardware andsoftware. The present invention may be implemented as computer softwareimplemented by one or more networked processing apparatuses. The networkcan comprise any conventional terrestrial or wireless communicationsnetwork, such as the Internet. The processing apparatuses can compromiseany suitably programmed apparatuses such as a general purpose computer,personal digital assistant, mobile telephone (such as a WAP or3G-compliant phone) and so on. Since the present invention can beimplemented as software, each and every aspect of the present inventionthus encompasses computer software implementable on a programmabledevice. The computer software can be provided to the programmable deviceusing any storage medium for storing processor readable code such as afloppy disk, hard disk, CD ROM, magnetic tape device or solid statememory device.

The hardware platform includes any desired kind of hardware resourcesincluding, for example, a central processing unit (CPU), a random accessmemory (RAM), and a hard disk drive (HDD). The CPU may be implemented byany desired kind of any desired number of processor. The RAM may beimplemented by any desired kind of volatile or non-volatile memory. TheHDD may be implemented by any desired kind of non-volatile memorycapable of storing a large amount of data. The hardware resources mayadditionally include an input device, an output device, or a networkdevice, depending on the type of the apparatus. Alternatively, the HDDmay be provided outside of the apparatus as long as the HDD isaccessible. In this example, the CPU, such as a cache memory of the CPU,and the RAM may function as a physical memory or a primary memory of theapparatus, while the HDD may function as a secondary memory of theapparatus.

In one example, the present invention may reside in a communicationmanagement system that manages a plurality of communication terminals.The communication management system includes: a candidate counterpartterminal manager to store, for each one of a plurality of communicationterminals, terminal identification information for identifying thecommunication terminal, and candidate counterpart terminalidentification information for identifying one or more candidatecounterpart communication terminals that may be requested to startcommunication with the communication terminal, in association with eachother; a terminal information manager to store, for each one of theplurality of communication terminals, the terminal identificationinformation of the communication terminal, and location informationindicating a location of the communication terminal on a network, inassociation with each other; a session manager to store sessionidentification information for identifying a communication sessioncarried by at least a first communication terminal and a secondcommunication terminal of the plurality of communication terminals, andterminal identification information of at least the first and secondcommunication terminals carrying the communication session, inassociation with each other; a receiver to receive a session startdetermination request that requests to determine whether to start acommunication session with a third communication terminal from aconversion system, the conversion system capable of converting acommunications protocol of contents data to be transmitted or receivedthrough at least two of the plurality of communication terminals, thesession start determination request including 1) location information ofthe third communication terminal that requests to participate in thecommunication session being carried by the first and secondcommunication terminals, and 2) session identification information foridentifying the communication session being carried by the first andsecond communication terminals; an obtainer to obtain the terminalidentification information of at least the first and secondcommunication terminals stored in association with the sessionidentification information received at the receiver, obtain candidatecounterpart terminal identification information of one or more candidatecounterpart communication terminals associated with the obtainedterminal identification information of at least the first and secondcommunication terminals, and obtain location information of the one ormore candidate counterpart communication terminals associated with theobtained candidate counterpart terminal information; a determiner todetermine whether the location information of the third communicationterminal received at the receiver matches any one of the obtainedlocation information of the one or more candidate counterpartcommunication terminals for at least the first and second communicationterminals carrying the communication session identified by the sessionidentification information received at the receiver; and a transmitterto transmit a response indicating to start a communication session withthe third communication terminal based on a determination resultindicating that the location information of the third communicationterminal matches one of the obtained location information, to theconversion system in response to the session start determinationrequest.

In one example, the candidate counterpart terminal manager correspondsto the candidate list management DB 5004, which may be implemented by amemory that operates in cooperation with a processor. The terminalinformation manager corresponds to the terminal information managementDB 5002, which may be implemented by a memory that operates incooperation with a processor. The session manager corresponds to thesession management DB 5005, which may be implemented by a memory thatoperates in cooperation with a processor. The processor may be the CPU201 (FIG. 8). The receiver corresponds to the data transmitter/receiver51, which may be implemented by the network I/F 209 (FIG. 8) accordingto an instruction received from the CPU 201. The obtainer corresponds tothe memory control 59, which may be implemented by an instructionreceived from the CPU 201 (FIG. 8) in cooperation with the HDD 205 (FIG.8). The determiner corresponds to the determiner 55, which may beimplemented by the CPU 201 (FIG. 8). The transmitter corresponds to thedata transmitter/receiver 51.

In one example, the third communication terminal may be thenon-dedicated terminal 10D, which communicates using a communicationsprotocol different that the communications protocol of the dedicatedterminal 10A.

What is claimed is:
 1. A communication management system, comprising: amemory configured to store, for each one of a plurality of communicationterminals including at least a first communication terminal of a firsttype that uses a first communication protocol and a second communicationterminal of a second type that uses a second communication protocol,terminal identification information for identifying the respectivecommunication terminal, and candidate counterpart terminalidentification information for identifying one or more candidatecounterpart communication terminals that may be requested to startcommunication with the respective communication terminal, in associationwith each other; the memory being further configured to store, for thesecond communication terminal that uses the second communicationprotocol among the plurality of communication terminals, the terminalidentification information of the second communication terminal, andaddress information indicating an address of the second communicationterminal that uses the second communication protocol on a network, inassociation with each other; the memory being further configured tostore session identification information for identifying a communicationsession, the communication session being carried by at least the firstcommunication terminal that uses the first communication protocol andthe second communication terminal that uses the second communicationprotocol of the plurality of communication terminals, and terminalidentification information of at least the first and secondcommunication terminals carrying the communication session, inassociation with each other; a receiver configured to receive a sessionstart determination request that requests to determine whether to starta communication session with a third communication terminal that usesthe second communication protocol from a conversion system, theconversion system including circuitry configured to convert between thefirst communication protocol and the second communication terminal inrelaying content data to be transmitted or received through at least twoof the plurality of communication terminals, the session startdetermination request including 1) address information of the thirdcommunication terminal that requests to participate in the communicationsession being carried by the first and second communication terminals,and 2) session identification information for identifying thecommunication session being carried by the first and secondcommunication terminals; circuitry configured to obtain the terminalidentification information of at least the first and secondcommunication terminals stored in association with the sessionidentification information received at the receiver, obtain candidatecounterpart terminal identification information of one or more candidatecounterpart communication terminals associated with the obtainedterminal identification information of at least the first and secondcommunication terminals from the memory, and obtain address informationof the one or more candidate counterpart communication terminals thatuses the second communication protocol associated with the obtainedcandidate counterpart terminal information from the memory; determinewhether the address information of the third communication terminalreceived at the receiver matches any one of the obtained addressinformation of any one of the one or more candidate counterpartcommunication terminals using the second communication protocol for atleast the first and second communication terminals carrying thecommunication session identified by the session identificationinformation received at the receiver; and a transmitter configured totransmit a response indicating to start a communication session with thethird communication terminal based on a determination result indicatingthat the address information of the third communication terminal matchesone of the obtained address information, to the conversion system inresponse to the session start determination request.
 2. Thecommunication management system of claim 1, wherein the first and secondcommunications protocol are each defined by a call control protocol usedfor connecting or disconnecting connections with a counterpartcommunication terminal, and an encoding format used for encodingcontents data to an IP packet, and at least one of the call controlprotocol and the encoding format differs between the first and secondcommunication protocol.
 3. The communication management system of claim1, wherein the address information includes an IP address.
 4. Acommunication system, comprising: the communication management system ofclaim 1; and the conversion system configured to start a communicationsession with the third communication terminal to transmit or receivecontents data using the second communication protocol.
 5. Thecommunication system of claim 4, wherein the conversion system convertsthe communications protocol of the contents data between the thirdcommunication terminal and the first communication terminal thatcommunicates using the first communication protocol.
 6. A communicationmethod, comprising: storing, in a memory, for each one of a plurality ofcommunication terminals including at least a first communicationterminal of a first type that uses a first communication protocol and asecond communication terminal of a second type that uses a secondcommunication protocol, terminal identification information foridentifying the respective communication terminal and candidatecounterpart terminal identification information for identifying one ormore candidate counterpart communication terminals that may be requestedto start communication with the respective communication terminal, inassociation with each other; storing, in the memory, for the secondcommunication terminal that uses the second communication protocol amongthe plurality of communication terminals, the terminal identificationinformation of the second communication terminal, and addressinformation indicating an address of the second communication terminalthat uses the second communication protocol on a network, in associationwith each other; storing, in the memory, session identificationinformation for identifying a communication session, the communicationsession being carried by at least the first communication terminal thatuses the first communication protocol and the second communicationterminal that uses the second communication protocol of the plurality ofcommunication terminals, and terminal identification information of atleast the first and second communication terminals carrying thecommunication session, in association with each other; receiving asession start determination request that requests to determine whetherto start a communication session with a third communication terminalthat uses the second communication protocol from a conversion system,the conversion system including circuitry configured to convert betweenthe first communication protocol and the second communication terminalin relaying content data to be transmitted or received through at leasttwo of the plurality of communication terminals, the session startdetermination request including 1) address information of the thirdcommunication terminal that requests to participate in the communicationsession being carried by the first and second communication terminals,and 2) session identification information for identifying thecommunication session being carried by the first and secondcommunication terminals; obtaining the terminal identificationinformation of at least the first and second communication terminalsstored in association with the session identification informationreceived at the receiver, obtain candidate counterpart terminalidentification information of one or more candidate counterpartcommunication terminals associated with the obtained terminalidentification information of at least the first and secondcommunication terminals from the memory, and obtain address informationof the one or more candidate counterpart communication terminals thatuses the second communication protocol associated with the obtainedcandidate counterpart terminal information from the memory; determiningwhether the address information of the third communication terminalreceived at the receiver matches any one of the obtained addressinformation of any one of the one or more candidate counterpartcommunication terminals using the second communication protocol for atleast the first and second communication terminals carrying thecommunication session identified by the session identificationinformation received at the receiver; and transmitting a responseindicating to start a communication session with the third communicationterminal based on a determination result indicating that the addressinformation of the third communication terminal matches one of theobtained address information, to the conversion system in response tothe session start determination request.
 7. The communication method ofclaim 6, wherein the first and second communications protocol are eachdefined by a call control protocol used for connecting or disconnectingconnections with a counterpart communication terminal, and an encodingformat used for encoding contents data to an IP packet, and at least oneof the call control protocol and the encoding format differs the firstand second communication protocol.
 8. A non-transitory recording mediumstoring a plurality of instructions which, when executed by acommunication management system, cause the communication managementsystem to perform a communication method comprising: storing, in amemory, for each one of a plurality of communication terminals includingat least a first communication terminal of a first type that uses afirst communication protocol and a second communication terminal of asecond type that uses a second communication protocol, terminalidentification information for identifying the respective communicationterminal, and candidate counterpart terminal identification informationfor identifying one or more candidate counterpart communicationterminals that may be requested to start communication with therespective communication terminal, in association with each other;storing, in the memory, for the second communication terminal that usesthe second communication protocol among the plurality of communicationterminals, the terminal identification information of the secondcommunication terminal, and address information indicating an address ofthe second communication terminal that uses the second communicationprotocol on a network, in association with each other; storing, in thememory, session identification information for identifying acommunication session, the communication session being carried by atleast the first communication terminal that uses the first communicationprotocol and the second communication terminal that uses the secondcommunication protocol of the plurality of communication terminals, andterminal identification information of at least the first and secondcommunication terminals carrying the communication session, inassociation with each other; receiving a session start determinationrequest that requests to determine whether to start a communicationsession with a third communication terminal that uses the secondcommunication protocol from a conversion system, the conversion systemincluding circuitry configured to convert between the firstcommunication protocol and the second communication terminal in relayingcontent data to be transmitted or received through at least two of theplurality of communication terminals, the session start determinationrequest including 1) address information of the third communicationterminal that requests to participate in the communication session beingcarried by the first and second communication terminals, and 2) sessionidentification information for identifying the communication sessionbeing carried by the first and second communication terminals; obtainingthe terminal identification information of at least the first and secondcommunication terminals stored in association with the sessionidentification information received at the receiver, obtain candidatecounterpart terminal identification information of one or more candidatecounterpart communication terminals associated with the obtainedterminal identification information of at least the first and secondcommunication terminals from the memory, and obtain address informationof the one or more candidate counterpart communication terminals thatuses the second communication protocol associated with the obtainedcandidate counterpart terminal information from the memory; determiningwhether the address information of the third communication terminalreceived at the receiver matches any one of the obtained addressinformation of any one of the one or more candidate counterpartcommunication terminals using the second communication protocol for atleast the first and second communication terminals carrying thecommunication session identified by the session identificationinformation received at the receiver; and transmitting a responseindicating to start a communication session with the third communicationterminal based on a determination result indicating that the addressinformation of the third communication terminal matches one of theobtained address information, to the conversion system in response tothe session start determination request.